Remote assessment of the Penn computerised neurocognitive battery in individuals with 22q11.2 deletion syndrome

BACKGROUND

Neurocognitive functioning is an integral phenotype of 22q11.2 deletion syndrome relating to severity of psychopathology and outcomes. A neurocognitive battery that could be administered remotely to assess multiple cognitive domains would be especially beneficial to research on rare genetic variants, where in-person assessment can be unavailable or burdensome. The current study compares in-person and remote assessments of the Penn computerised neurocognitive battery (CNB).

METHODS

Participants (mean age = 17.82, SD = 6.94 years; 48% female) completed the CNB either in-person at a laboratory (n = 222) or remotely (n = 162).

RESULTS

Results show that accuracy of CNB performance was equivalent across the two testing locations, while slight differences in speed were detected in 3 of the 11 tasks.

CONCLUSIONS

These findings suggest that the CNB can be used in remote settings to assess multiple neurocognitive domains.

Influence of gestational diabetes mellitus on neonatal weight outcome in twin pregnancies

AIMS

To evaluate the influence of gestational diabetes mellitus on neonatal birthweight, macrosomia and weight discrepancy in twin neonates.

METHODS

An observational retrospective study was performed. One hundred and six women with gestational diabetes and twin pregnancy and 166 twin controls who delivered viable fetuses > 24 weeks were included. Impact of maternal pre-pregnancy BMI, smoking habit, method of conception, chorionicity, gestational age at delivery, mode of delivery and hypertensive complications were also analysed. The effect of maternal hyperglycaemia and metabolic control in gestational diabetes pregnancies was assessed.

RESULTS

Gestational hypertension and pre-eclampsia were significantly higher in the group with gestational diabetes (21.5% vs. 6.3%, P = 0.007 and 6.2% vs. 0%, P = 0.025). There were no differences in the incidence of macrosomia (5.7% vs. 7.2%, P = 0.803), large for gestational age (10.3% vs. 13.2%, P = 0.570), small for gestational age (10.3% vs. 12.0%, P = 0.701), severely small for gestational age (6.6% vs. 7.8%, P = 0.814) or weight discrepancy (20.6% vs. 15.2%, P = 0.320) in the group with gestational diabetes compared with twin pregnancies without diabetes. There were no differences when comparing insulin-requiring gestational diabetes pregnancies and twins without diabetes for any of the neonatal weight outcomes. There was no relationship between third trimester HbA1c and neonatal birthweight or infant birthweight ratio.

CONCLUSION

Gestational diabetes did not increase the risk of macrosomia or weight discrepancy of twin newborns. Furthermore, glycaemic control did not influence the rate of any of the weight outcomes in our study population. In twin pregnancies, gestational diabetes was associated with a higher risk of gestational hypertension and pre-eclampsia.

What is the relative contribution of blood glucose levels at different time points of the day to HbA1c in Type 1 diabetes?

AIMS

To evaluate the relative contribution of blood glucose levels at different time points of the day to HbA(1c) in Type 1 diabetes.

METHODS

Consecutive home blood glucose records (n = 146) from 71 Type 1 diabetic patients who were on an intensive diabetes therapy programme were examined. Each home blood glucose record included six daily blood glucose profiles over 2 months. The relationship between glycaemic values at each time point and HbA(1c) measured at the end of each record period was analysed.

RESULTS

Significant linear correlations were found between HbA(1c) and glycaemia at each time point of the day (ranged from 0.413 to 0.593), the strongest being with predinner glycaemia (r = 0.593; P = 0.000). Total daily glycaemia, mean preprandial and mean postprandial glycaemia were also significant and linearly correlated with HbA(1c) (r = 0.701; r = 0.686; r = 0.620, respectively; P < 0.0001). Multiple linear regression analysis showed that predinner, prebreakfast and post-breakfast glycaemia correlated significantly and independently with HbA(1c). The model accounted for 47.8% of the variance in HbA(1c).

CONCLUSIONS

Our study shows that among individual time points, prebreakfast and predinner are those with more influence on HbA(1c) in Type 1 diabetes and, to a lesser extent, post breakfast. It also confirms that preprandial glycaemia better predicts overall glycaemic control in Type 1 diabetes than postprandial glycaemia.

Resection of Kommerell's diverticulum and left subclavian artery transfer for recurrent symptoms after vascular ring division

OBJECTIVES

A Kommerell's diverticulum in patients with a right aortic arch may become aneurysmal and be an independent cause of tracheoesophageal compression, even after ligation and division of a left ligamentum. We review the indications for and results of Kommerell's diverticulum resection and left subclavian artery transfer in children with a right aortic arch who previously underwent vascular ring (ligamentum) division.

METHODS

From 1998 through 2001, eight children have been referred with recurrent respiratory symptoms (n=8) and/or recurrent dysphagia (n=4) after vascular ring division. Each child had a right aortic arch with a left ligamentum and had undergone division of the ligamentum elsewhere. All had a Kommerell's diverticulum that was not addressed at the initial operation. All patients had a repeat left thoracotomy with resection of the diverticulum. Five patients had division and reimplantation of the left subclavian artery into the left carotid artery to relieve the sling-like effect of the retroesophageal left subclavian artery on the right aortic arch. One other patient had primary Kommerell's diverticulum resection and transfer of the left subclavian artery to the left carotid artery.

RESULTS

The mean age at the initial operation was 1.7+/-0.9 years, and the mean age at reoperation was 8.0+/-3.7 years. In all patients postoperative bronchoscopy confirmed relief of the tracheal compression. There were no complications related to the subclavian artery transfer. Two patients developed postoperative chylothorax, one requiring thoracic duct ligation. The median hospital stay was 5 days. All patients had dramatic resolution of their preoperative symptoms.

CONCLUSIONS

Kommerell's diverticulum is an important anatomic structure that can cause recurrent symptoms in patients with a right aortic arch after ligamentum division. In selected patients, reoperation with resection of the Kommerell's diverticulum and transfer of a retroesophageal left subclavian artery results in relief of symptoms. This technique has become our procedure of choice as a primary operation for children with a right aortic arch and a significant Kommerell's diverticulum.

Increased numbers of caveolae in retinal endothelium and pericytes in hypertensive diabetic rats

PURPOSE

Long-term clinical studies have now shown that tight control of blood pressure in type 2 diabetes reduces the risk of diabetes-related death and common diabetic complications, including diabetic retinopathy. However, the mechanisms by which hypertension enhances diabetic microvascular disease, especially diabetic retinopathy, are poorly understood. We developed an experimental model of hypertension in diabetic rats and studied the early ultrastructural changes in retinal capillaries under these conditions.

METHODS

Hypertension was induced in diabetic BioBreeding (BB) rats by unilateral nephrectomy, weekly subcutaneous mineralocorticoid and 0.9% oral saline. Serial blood pressures and ultrastructural features of retinal capillaries were recorded in four groups: normotensive Wistar rats, normotensive diabetic rats, hypertensive Wistar rats and hypertensive diabetic rats.

RESULTS

A significant and sustained increase in systolic blood pressure occurred in both groups of nephrectomised rats. There was a significant increase in the number of caveolae (i) in both pericytes and endothelial cells in animals with hypertension and diabetes together compared with all other groups and (ii) in pericytes in animals with diabetes alone. The number of direct contacts between pericytes and endothelial cells was reduced in diabetic and hypertensive diabetic animals. Hypertension and diabetes had an interactive effect in producing retinal capillary basement membrane thickening.

CONCLUSIONS

In the BB rat hypertension and diabetes have an interactive effect in increasing the number of caveolae in both endothelial cells and pericytes. We speculate that this may be a reflection of changes in calcium and nitric oxide metabolism in these animals.

[Nutritional management of radiation-induced enteritis: apropos of a case]

We present a case of a 46-year-old woman who is hospitalized in March of 1997 for a picture of severe mixed malnutrition. We describe the clinical history since the diagnosis of an endometrium carcinoma in 1995, treated with radiation therapy, with the aim of determining the etiology of the severe malnutrition picture, as well as the different complications she presented in the course of her hospitalization that justify the decisions made in the choice of the nutritional support.

Hepatobiliary dysfunction as the initial manifestation of disseminated cryptococcosis

A case of hepatobiliary dysfunction as the initial manifestation of disseminated cryptococcosis is described. The patient was admitted with symptoms of hepatitis with cholestatic jaundice. Antibody tests for hepatitis B and C and human immunodeficiency virus were negative. The patient continued to deteriorate clinically. Eventually, the patient succumbed to hepatic failure. Autopsy disclosed systemic cryptococcosis that caused extensive necrosis of the liver. In review of the literature, only nine cases of cryptococcal infection presenting as hepatitis, cholangitis, and cholecystitis as initial manifestation were reported. Four of these patients had been subjected to exploratory laparotomy for clinical suspicion of acute abdomen. One patient developed cirrhosis as a result of cryptococcal hepatitis. Two patients succumbed to hepatic failure. Cryptococcosis is known to occur commonly in immunocompromised patients, yet only two reported cases presenting as hepatitis were associated with immunocompromised status.

[Critical analysis of the evolution of commercial preparations for enteral nutrition during 1988-1996]

Enteral nutrition is a form of nutritional support that is continually growing and expanding, and within this area especially the enteral preparations or formulae. The object of the present is to analyze the evolution of the commercially available nutritionally complete enteral preparations between 1988 and 1997, illustrating the variations that have occurred both from the quantitative and form the qualitative points of view. A progressive increase is seen in the absolute number of available enteral formulae, with the increase in both polymeric formulae with dietary fiber, and that of formulae designed for specific diseases being significant (p < 0.05). The standard polymeric formulae and the oligomeric formulae decrease, but not in a significant manner. There is a special discussion or the characteristic and the usefulness of the polymeric formulae with dietary fiber ad the formulae designed especially for specific diseases. The clinical efficacy of most of these special formulae is controversial, with there not being sufficient objective clinical evidence at present that justifies their routine use.

Efficacy of octreotide in the regression of a metastatic carcinoid tumour despite negative imaging with In-111-pentetreotide (Octreoscan)

We present the case of a 52-year old patient diagnosed with carcinoid tumour of the rectum with liver metastases in which treatment with somatostatin analogues (octreotide) proved very effective in the disappearance of the symptomatology and dramatic efficacy in the regression of the tumour. Imaging by octreoscan was always negative. The role of octreotide in the treatment of carcinoid tumour and the usefulness of In-111-pentetreotide (octreoscan) in the localization and prediction of the response to treatment with octreotide is discussed. We conclude that the negative result of the scintigraphic image with octreoscan does not necessarily suppose the inefficacy of octreotide treatment. We believe that this may constitute an important issue since some patients may be denied octreotide treatment in the absence of a positive octreoscan result.

Hürthle cell tumors

OBJECTIVES

a) To provide a clinicopathological profile of Hürthle cell neoplasms (HCT) in our experience. b) To evaluate if there are any differences in the clinical or morphological features between three HCT categories: benign, malignant and indeterminate. c) To examine the role of the clinical and morphological features in predicting the behavior of these neoplasms.

METHODS

We reviewed the clinical reports of all patients with a histological diagnosis of HCT at our Hospital between 1981 and 1996. The final study group consisted of 25 cases. The neoplasms were divided into three categories on the basis of presence and degree of capsular and vascular invasion, marked nuclear atypia, tumour necrosis and pattern of growth. A series of clinical parameters were evaluated.

RESULTS

Of the 25 tumors, 52% were morphologically classified as benign, 8% as indeterminate and 40% as malignant. Follow-up ranged from 10 months to 14.8 years or until death (average 3.8 years). There were four local recurrences (20%), three in the malignant group (30%) and one in the benign group (7.6%) (p = 0.15). One patient presented metastases and died because of tumor during the follow-up. Apart from capsular and vascular invasion and some aspects of therapy, no significant differences were found in the clinical and histological parameters analyzed between the three histological groups or between the groups with or without recurrence.

CONCLUSION

We did not find any clinical or morphological parameter which can predict recurrence among these tumors. Our study further establishes the controversial issues surrounding the biological behavior of Hürthle cell neoplasms.

Decreased heart-period variability in patients with panic disorder: a study of Holter ECG records

This study investigated cardiac autonomic function in patients with panic disorder and normal controls using Holter ECG records. A decrease in ultra-low frequency power (< 0.0033 Hz) is known to be associated with an increased risk for cardiovascular mortality in humans. Twenty-four-hour ECG was recorded in 29 patients with panic disorder and 23 normal controls using Holter records. Data for 20 h and also 20000 s of awake and 20000 s of sleep periods were analyzed using spectral analysis to quantify absolute and relative heart-period variability in ultra low (ULF: < 0.0033 Hz), very low (VLF: 0.0033-0.04 Hz), low (LF: 0.04-0.15 Hz) and high (HF: 0.15-0.5 Hz) frequency bands. The patients with panic disorder had significantly lower total and absolute ULF power, which was more pronounced during sleep. The patients also had significantly lower relative ULF power and significantly higher relative LF power during sleep. There was a significant increase of relative LF power from awake to sleep period only in the patient group. The decrease in total and ULF power may increase the risk of mortality and sudden arrhythmic death in patients with panic disorder if they experience a cardiac event. The higher relative LF power during sleep also suggests a possible higher sympathetic drive in the patients during sleep.

[Characterization of steroid 21-hydroxylase gene mutations in a oligosymptomatic form of congenital adrenal hyperplasia: family study]

BACKGROUND

21-hydroxilase deficiency accounts for over 90% of all cases of congenital adrenal hyperplasia (CAH). There is a non-negligible incidence of both severe and nonclassical forms of this genetic disorder. Enzyme deficiency is due to mutations in the gene encoding adrenal 21-hydroxylase (named CYP 21B) and is inherited in an autosomical recesive way. Complete or partial impairment of enzyme activity has been correlated with the different clinical forms of the disease.

PATIENTS AND METHODS

In the present paper CYP 21B gene analysis results obtained in a family with two kindred affected by a nonclassical form of the disease are shown. Clinical assessment of these two kindred showed a very mild form of the disease, whereas biochemical results suggested a late-onset partial 21-hydroxylase deficiency. Genotyping for deletions and 10 point mutations in the CYP 21B gene was performed by Southern blot analysis and polymerase chain reaction (PCR) allele-specific oligonucleotide (ASO) hybridation technique.

RESULTS

Molecular genetic analysis performed in the two affected patients and two further relatives allowed us to detect the presence of different mutations in the two alleles of the CYP 21B gene. One of these mutations was severe (655G) and came from maternal line, whereas the other was mild (Val281Leu) and originated in paternal line.

CONCLUSION

Molecular genetic analysis allows the possibility of finding severe (and non-expected) mutations in patients with clinically mild and late-onset forms of the 21-hydroxylase deficiency.

[Results of nutritional treatment of anorexia nervosa: our experience (1989-1995)]

With the alm of evaluating the nutritional treatment of anorexia nervosa (AN) in our center, evolutive data were collected, as well as anthropometric and biochemical parameters, of out out patient department (OPD) as well as of our hospital admissions (HA) which took place between 1989-91 (period A) and between 1992-95 (period B). 79 cases of HA were included (5 men, 31 women), with a duration of hospitalization of 36.96 +/- 22.02 days, with the reason for release most often (86.84%) being reaching the agreed upon weight, and 124 cases of OPD (12 men and 112 women), who were followed for 11.53 +/- 12.13 months achieving a final release rate of 14.14%. The nutritional status (NS) of the HA patients upon admission was most often sever caloric malnutrition (CM) (64.55%), and upon release this was moderate CM (60.75%), while in the OPD the moderate CM was most frequent at the initial visit and at the last visit registered. The anthropometric parameter which was most affected, was the triceps fold (TF), followed by the wight (W). The biochemical abnormalities were few, with hypercholesterolemia and ferropenia being notable. The nutritional treatment in the OPD required the addition of dietary supplements in 31% of the cases, and of psycho-medication in 43%. In the HA cases, only 6 patients reached the agreed upon wight with a free oral diet, and 35 patients required dietary supplements, 20 needed mixed therapy (enteral nutrition and supplements), and 17 cases required enteral nutrition through a naso-gastric tube. Significant multivariant models are presented which find independent associations for the probability of release (lower age upon diagnosis, male, lower income, absence of bulimia's, no need for dietary supplements), of amenorrhoea (worse NS, absence of vomiting), and for the HA time (more interventionist treatment, lower weight, lower age). The comparison between periods, shows an initial contact of the patients with AN with our OPD, with a better nutritional status y recent years, as well as a better nutritional result, a greater tendency towards the use of enteral nutrition, and a shorter time of HA.

Diffuse histoplasmosis in a patient with sarcoidosis

A case is presented of a woman with a long history of sarcoidosis who developed diffuse histoplasmosis. Although association between these two entities has been described before, there are only a few case reports of histoplasmosis among sarcoid patients. Diagnosis was finally established by bone marrow biopsy which saved the patient's life.

Adolescent depression: relationships of self-report to intellectual and adaptive functioning

Self-report measures of depression, general psychopathology, and social skills were administered to adolescents ranging from moderate mental retardation to above normal intelligence. Adolescents with mental retardation reported more depression and general psychopathology symptoms. Variance and regression analyses demonstrated distinctions on the basis of mental retardation status for individual measures. Additional analyses identified differences between individuals with above normal intelligence and individuals with mild mental retardation on the basis of depression specifically. Adaptive behavior functioned as a moderator variable, mediating the relationship between depression and intellectual functioning.

A method for obtaining a pure population of t6/t6 mouse embryos prior to developmental arrest

Developmental delay, as the result of ovariectomy, causes mouse blastocyst embryos obtained from +/t6 inter se matings to separate into two distinct populations when placed into outgrowth medium. One population remains as free floating embryos for a significantly longer period of time than the other population. Based upon their phenotypic expression following attachment and outgrowth, the former population was considered to be composed entirely of t6/t6 embryos and the latter, to be composed of +/+ and +/t6 embryos (Nadijcka et al., '81). In the present study, two-dimensional gel electrophoresis identified the embryos which were delayed in attachment as t6/t6 embryos since they synthesize only p63/6.9a, a product of the Tcp-1a locus which is unique to t-haplotypes. The early attaching embryos, assumed to be +/+ and +/t6, synthesize both p63/6.9a and b. The p63/6.9b protein is coded for by Tcp-1b on the wild-type homologous chromosome. Control +/+ blastocyst embryos synthesize only p63/6.9b. The data show that t6/t6 embryos can be identified prior to their lethal period and, thus, subjected to comparative studies to determine the cause of their lethality. Developmental delay is the first method established to enable one to unambiguously identify t6/t6 embryos prior to developmental arrest.

Glass-bead column separation of motile and nonmotile human spermatozoa

Glass-bead columns were tested for their efficiency in concentrating motile human spermatozoa from frozen semen samples. The data show that glass-bead filtration concentrates the motile gametes in each sample and is significantly more efficient than the swim-up method for obtaining populations of motile spermatozoa. The data suggest that this method can be applied clinically to obtain motile spermatozoa from poor-quality semen for use in in vitro fertilization.

The in vivo and in vitro transmission ratio distortion of one complete and two partial t haplotypes in mice

The effects of different types of insemination (normal and delayed matings and in vitro fertilization) on the transmission ratio distortion (TRD) of three t haplotypes were determined. The tw73 haplotype which contains all of the loci known to affect TRD is transmitted at equivalent frequencies in normal matings and in in vitro fertilizations (0.84 and 0.85, respectively) but at a significantly lower frequency (0.62) in delayed matings. The distal partial th18 haplotype is transmitted at equivalent frequencies in all types of insemination (0.66 to 0.70) while the proximal partial tw18 haplotype is transmitted in Mendelian frequencies in normal matings and in in vitro inseminations but at a significantly lower frequency in delayed matings. The results are discussed with reference to the current genetic model for transmission ratio distortion.

The ability of glass-bead column-filtered mouse spermatozoa to fertilize homologous eggs in vitro

Glass-bead columns have been used to separate mouse spermatozoa into motile and nonmotile fractions. The spermatozoa in the motile fraction are able to fertilize eggs in vitro. Significantly more of the two-cell embryos which develop from these zygotes reach the blastocyst stage than do two-cell embryos developing from eggs fertilized in vitro with unfiltered control spermatozoa.

The extended survival of tw5/tw5 mouse embryo cells in vitro

The tw5 haplotype is a recessive mutation which is lethal when homozygous in mouse embryos following implantation. This series of studies was undertaken to determine the effect of the tw5/tw5 genotype on embryos developing in vitro. Blastocyst embryos from +/tw5 inter se matings were compared with control blastocysts obtained from matings between T/+ and +/+ females and +/tw5 males for their abilities to continue development in vitro in two culture media. The data show that there are no significant differences between the percentages of experimental and control blastocyst embryos which attach and outgrow or which contain inner cell masses on any day of culture up to equivalent gestation day 21 in either media. These findings show that the life span of cells from tw5/tw5 embryos can be extended significantly by in vitro culture.

Acrosin activity in spermatozoa from sterile t6/tw32 and fertile control mice

Spermatozoa from sterile t6/tw32 and control fertile +/+, T/tw32, T/t6 mice were compared for their abilities to hydrolyse protein matrices and for their levels of acrosin activity. The data show that the immature and mature gametes from both the experimental and control males hydrolyse protein matrices. The quantitative acrosin assays show, however, that the mature gametes from the intercomplement males have significantly less total acrosin activity than any of the control groups of gametes. These findings suggest that this reduced acrosin activity is an additional phenotypic expression of the intercomplement genotype which results in male sterility.

Cutaneous T cell lymphoma with suppressor phenotype and function

Cutaneous T cell lymphomas (CTCL) are typically malignancies of postthymic helper T cells which retain helper function when assayed in vitro. We have described a case clinically and morphologically consistent with CTCL, but in which the tumor cells unequivocally had a suppressor T cell phenotype and suppressor function. This case could be differentiated from other varieties of peripheral T cell lymphomas by multiple clinical and laboratory parameters. The increasingly routine use of immune phenotyping in the evaluation of malignant lymphomas will likely result in the identification of additional cases of this entity, which should be studied to assess its clinical and prognostic relationship to the more common helper cell CTCL.

The in vivo and in vitro transmission frequencies of the tw5-haplotype in mice

The recessive tw5-haplotype, a complete haplotype, is transmitted by heterozygous male mice at very high frequencies (greater than 0.90) in normal matings. The present studies were undertaken to determine the effects of delayed matings and in vitro fertilizations on this phenotypic expression. Males carrying the tw5-haplotype (+/tw5) were first tested for their frequencies of transmission of the mutant 17th chromosome in both normal and delayed matings. Spermatozoa obtained from these same males were then used to fertilize eggs in vitro. The in vivo and in vitro transmission frequencies were found to be statistically equivalent in all types of inseminations. An in vitro fertilization time course study showed that the same percentages of eggs are fertilized by tw5-bearing spermatozoa when the gametes are coincubated for either 2 or 6 h. The data lead to the conclusion that the transmission frequency of the tw5-haplotype is not affected either by the length of time elapsing between insemination and fertilization or by the environment in which fertilization occurs.

The transmission ratio distortion of the th2-haplotype in vivo and in vitro

The th2-haplotype is transmitted at low frequencies (less than 0.30) by +/th2 males in normal matings. In the studies described here, the transmission frequency of the th2-haplotype from Rb7/th2 males was determined for normal and delayed matings and in vitro inseminations. The data show the transmission frequency from the two in vivo inseminations to be less than 0.30 and to be statistically equivalent. However, the in vitro transmission frequency (0.80) is significantly greater than either of the in vivo frequencies. The results show that the environment in which fertilization occurs affects the transmission frequency of this specific t-haplotype significantly.

Paroxysmal nocturnal hemoglobinuria associated with the acquired immunodeficiency syndrome

Pancytopenia is a well-recognized manifestation of clinical illness related to human immunodeficiency virus infection. The mechanism of this has been debated, but has been thought to relate either to a nonspecific marrow suppressive effect of opportunistic infections, or to direct involvement of bone marrow hematopoietic precursors as a target of human Immunodeficiency virus. We report the unique temporal association of the acquired immunodeficiency syndrome and paroxysmal nocturnal hemogloblnuria.

A method for karyotyping mouse blastocyst embryos developing from in vivo and in vitro fertilized eggs

A method for karyotyping blastocyst-staged mouse embryos is described. The use of this protocol results in the recovery of a high percentage (greater than 70%) of readable karyotypes and can be completed rapidly.

Prolymphocytic leukemia: postmortem findings after long-term survival

A patient had prolymphocytic leukemia and survived for 44 months. A partial remission for more than 11 months and a short complete remission were induced by agents commonly used for the treatment of acute myelocytic leukemia. However, surface markers identified the disease as of B-cell origin.

The effects of dehydration on the dynamics of transcapillary refill

Since the water reserve of the interstitium plays a major role in circulatory homeostasis, its reduction by dehydration may produce severe changes in the organism's response to hemorrhage but this has not been measured experimentally. Twelve immature pigs (22 +/= 2 Kg) were divided into two groups of six each. Control animals had free access to food and water prior to bleeding. Dehydrated animals had water withheld for 48 hours preceding the bleeding. All animals were bled 30 per cent of their calculated blood volumes while awake. No resuscitation was performed. No mortality was observed in the control group of animals, while four of the six dehydrated animals died (66%). All deaths occurred between one and four hours posthemorrhage. Plasma refill reached 33 per cent by 0.5 hours in the control group compared to only 17 per cent by 0.5 hours in the dehydrated group (p less than or equal to .05). Refill in the control group reached 50 per cent by three hours, whereas dehydrated animals surviving to three hours demonstrated no further refill (p less than or equal to .05). BUN, calcium, sodium, and osmolality were consistently higher in dehydrated than control animals (p less than or equal to .05). It is concluded that a reduction in the interstitial water reserve significantly impairs ability to recover from hemorrhage.

The phenotypic expression of a t6/t6/t6 genotype

In vivo, embryos which are homozygous for the t6 mutation die during egg cylinder development (gestation days 5.5--6.5). In vitro, these mutant embryos can be distinguished from their wild-type littermates by their developmental arrest and by the failure of their trophoblast cells to transform to giant cells. We have investigated the nature of this lethality by constructing triploid embryos with varying combinations of the t6 mutant chromosome. The phenotypes of outgrowths from these triploid embryos were examined and compared with the phenotypes of outgrowths from +/+, +/t6, and t6/t6 embryos. The data show 1) that +/t6/t6 embryos are phenotypically wild-type, while t6/t6/t6 embryos are phenotypically mutant and 2) that t6/t6/t6 and t6/t6 embryos are developmentally arrested at the same stage of outgrowth.

The effect of delay on the expression of the t6/t6 genotype

In vivo, t6/t6 embryos are developmentally arrested between gestation days 5.5 (short-egg-cylinder stage) and 6.75 (long-egg-cylinder stage). In the present series of studies we used both in vivo and in vitro blastocyst delay followed by in vitro outgrowth to determine whether the t6/t6 lethality is time- or stage-specific. The results show that the t6/t6 genome is expressed differently in vivo and in vitro and that the in vitro expression of the homozygous t6 genome differs with different methods of effecting developmental delay. Although delay increases the life span of t6/t6 embryos it does not alter the stage of lethality. One method used to effect delay (ovariectomy) causes the t6/t6 embryos to remain as blastocysts for a significantly longer period of time than their wild-type littermates when placed into outgrowth medium. This distinction provides a unique method for obtaining a sample composed entirely of t6/t6 embryos at a stage prior to the lethal period.

The in vitro transmission frequency of the t12 mutation in the mouse

Male mice which are heterozygous for a recessive lethal mutation (+/tL) transmit the tL mutation in non-Mendelian ratios. In the present studies, spermatozoa obtained from +/t12 males were used to fertilize ova from +/t12 females in vitro. The frequency of transmission of the t12 mutation determined from these in vitro studies was compared with the frequency of transmission of this mutation in normal and delayed matings. The data show that the transmission frequency of the t12 mutation, in vitro, is Mendelian and is the same as the transmission frequency of the t12 mutation in vivo when matings are delayed until the time of ovulation.

Sterility in mutant (tLx/tLy) male mice. I. A morphological study of spermiogenesis

The results from a comparative ultrastructural study of spermiogenesis in 6-, 10-, 14- and 17-month-old sterile t6/tw32, and fertile T/t6, T/tw32 and BALB/c, mice are reported. The studies show that all of the males contained the same types of defective spermatids and that defects were not limited to specific spermatid stages. Younger males had fewer abnormal spermatids than older males of the same genotype and at each age the BALB/c and t6/tw32 males appeared to contain more abnormal spermatids than the other males. No unique spermatid defect or increased frequency of a specific defect was found which can be correlated with infertility of the t6/tw32 males.

Sterility in mutant (tLx/tLy) male mice. II. A morphological study of spermatozoa

A comparative light and electron microscopy study was done on cauda epididymal spermatozoa obtained from correspondingly-aged sterile t6/tw32, and fertile T/tw32, T/t6 and BALB/c, mice. The results show that all of the males, regardless of age, contained defective gametes and that all contained the same types of aberrant gametes. The oldest males of each genotype contained more abnormal gametes than the younger males of the same genotype. No unique spermatozoan defect and no increased frequency of a specific spermatozoan defect was noted which could be correlated with the sterility of the t6/tw32 animals.

Sterility in mutant (tLx/tLy) male mice. III. In vitro fertilization

Mice which are heterozygous for two complementary lethal t mutations (t6/tw32) exhibit complete male sterility. Experiments have been conducted to determine if spermatozoa from these heterozygous males can fertilize oviducal ova in vitro. The experiments have been designed so that specific barriers which are present during in vivo fertilization can be sequentially removed and the fertilizing ability of the spermatozoa tested after each barrier is eliminated. Our results show that spermatozoa from t6/tw32 males are unable to effect fertilization even after all of the barriers normally imposed by the female reproductive tract have been removed.

The metabolism of exogenous fatty acids by preimplantation mouse embryos developing in vitro

The utilization of fatty acids from the culture medium has been examined in preimplantation mouse embryos developing in vitro. Incorporation of exogenous fatty acid into embryo lipids was examined by culturing 8-cell mouse embryos for 2h in a medium containing 0.1 mM [9, 10-3H]palmitic acid (900 mCi/mmol). Lipids were extracted from the embryos, and the total lipid extract was fractionated into various neutral lipid and polar lipid classes by thin-layer chromatography. Most of the radioactivity, over 93%, was recovered in neutral glycerides (mono- di-, and triacylglycerols). About 2% of the total radioactivity was recovered in other neutral lipid species including fatty acids, fatty alcohols, and sterol esters. The remainder of the radioactivity was recovered in polar lipids. Seventy-four per cent of the polar lipid radioactivity was present in the amine phosphatides, inositol and/or serine phosphatides, sphingomyelin, choline lysophosphatides, sulfatides, cerebrosides, and monoglycosylglycerides. Chemical degradation studies of labelled embryo lipids indicated that the tritium lable was entering into embryo lipids as the fatty acid and not via metabolic recycling. The oxidation of exogenous fatty acids by mouse embryos was assessed by incubating variously staged embryos for 4h in medium containing 0.1 mM [U-14C]palmitic acid (50 mCi/mmol) and quantitating the production of 14CO2. The rate of fatty acid oxidation was found to be relatively constant from the unfertilized egg up to the 8-cell stage and then increase significantly between the 8-cell and late blastocyst stages. The results suggest that preimplantation mouse embryos developing in vitro can utilize fatty acids from the medium both for incorporation into embryo lipids and for energy production via oxidation.

A study of spermatozoan defects in wild-type and T:t-bearing mice

A comparative light and electron microscopic study was done on cauda epididymal spermatozoa from +/tx, T/+, T/tx, C57BL/6J, BALB/c and randomly breeding Swiss Albino mice. The results show that all of the males contain abnormal spermatozoa and that all contain the same types of defective gametes. No unique defect was found which can be correlated with the increased transmission frequency of the tx-bearing allele.

A comparative study of spermiogenesis in wild-type and T:t-bearing mice

The results of a comparative ultrastructural study of spermiogenesis in T/tx, +/tx, +/T, C57BL/LJ, BALB/c and randomly breeding Swiss Albino mice are reported. The observations show that aberrant spermiogenesis occurs in males of all strains and genotypes and that the same specific types of abnormal spermatids are found in all of the males examined. No unique morphological defect which could be correlated with the increased transmission frequency of tx-bearing gametes can be found in males heterozygous for the tx allele.

Nature of lethality of t mutations in embryos

Mutations in the genes of the T complex in mice can lead to death at various stages of embryogenesis. It has been suggested that the T genes specify cell surface antigens which are essential for normal organisation of certain cells within the embryo. But, there is now evidence that at least some of these T complex mutations are simply generalised cell lethals.

Studies of t6/t6 mouse embryos

The phenocritical period of the t6/t6 genome extends from the late blastocyst substages through the elongated egg-cylinder stage. Most of the homozygous mouse embryos die during the short egg-cylinder stage. The viable egg-cylinder staged t6/t6 embryos can be distinguished from their phenotypically wild-type litter-mates at both the light and electron microscopic levels. The distinguishing characteristics of these embryos are aberrantly arranged entodermal cells, excessive cytoplasmic lipid and crystal-containing mitochondria. These same features are also characteristic of those mutant embryos which are developmentally arrested at both the short and elongated egg-cylinder stages. Over 50% of the t6/t6 embryos can be identified as early as the late blastocyst substages by the presence of large, electron-dense cytoplasmic lipid droplets.

ATP metabolism in tn/tn mouse embryos

Total ATP, ATP/ADP ratios, and the rates of synthesis and turnover of ATP were determined for t12-, tw32- and T+/T+-litters at the 2-cell, 4-cell, 8-cell, early morula, late morula and late blastocyst stages. The results show that tn-litters have excessive rates of ATP metabolism up to the cleavage stage immediately before the stage of lethality for most tw32/tw32 embryos (early morula) and most t12/t12 embryos (late morula); mutant ATP metabolism then falls below control levels. After the death of the tn homozygotes, ATP metabolism in the tn-litters (composed of only T+/T+ and T+/tn embryos) returns to control levels. These data are discussed in relation to the phenotypes of the homozygous tn embryos.

Autoradiographic studies of tn/tn mouse embryos

High-resolution autoradiographic studies were used to determine whether t12/t12 and tw32/tw32 mouse embryos synthesize the excessive lipid which distinguishes these embryos prior to their death. The studies show that the tn homozygotes synthesize neutral lipid which is stored in intracellular lipid droplets. Cholesterol and phospholipid precursors are not incorporated into these droplets.

Ultrastructural studies of tw32/tw32 mouse embryos

Homozygous tw32/tw32 mouse embryos, obtained from both spontaneously ovulated and superovulated T+/tw32 females mated to T+/tw32 males, have a lethal period which extends from the 8-12 cell stage to the late morula stage. Most of the homozygous mutant embryos die at the early morula stage and are characterized by excessive amounts of cytoplasmic lipid, mitochondrial abnormalities, binucleated cells and nuclear lipid droplets. The excessive cytoplasmic lipid and nuclear lipid droplets distinguish 35-50% of the embryos (presumably tw32 homozygotes) from their litter-mates prior to the lethal period. The remainder of the distinguishing characteristics appear in the later (8-cell to late morula) tw32/tw32 embryos in frequencies high enough to be considered phenotypic expressions of the mutant genome. The present study indicates that the non-complementary tw32 and t12 alleles are in fact separate T locus recessive alleles.