The incidence of uniparental disomy associated with intrauterine growth retardation in a cohort of thirty-five severely affected babies

OBJECTIVE

Our purpose was to screen for uniparental disomy 35 babies with idiopathic intrauterine growth retardation < 5th percentile.

STUDY DESIGN

The placenta and the baby's blood were conventionally karyotyped. Deoxyribonucleic acid from the parents, the baby's blood, and the placenta were then screened for uniparental disomy for 12 candidate chromosomes with use of chromosome-specific polymorphic deoxyribonucleic acid markers.

RESULTS

Two cases of maternal uniparental disomy for chromosome 16 were found associated with confined placental mosaicism for chromosome 16. No other uniparental disomy was found for any of the 12 chromosomes tested. Four structural chromosome abnormalities were also found in this cohort through standard karyotyping.

CONCLUSION

Uniparental disomy for the chromosomes tested does not explain the etiology of the majority of cases of intrauterine growth retardation < 5th percentile. Maternal uniparental disomy for chromosome 16 accounts for 5% of this cohort. Structural chromosomal abnormalities are also much higher than expected at 11%.

Secondary hyperalgesia to mechanical but not heat stimuli following a capsaicin injection in hairy skin

A psychophysical investigation was carried out to examine whether heat hyperalgesia exists within the secondary mechanical hyperalgesia zone surrounding a capsaicin injection site on hairy skin. A non-contact laser stimulator was used to deliver temperature controlled stimuli to sites within and outside the zone of mechanical hyperalgesia. Heat testing was carried out before and after the intradermal injection of 50 micrograms of capsaicin into the volar forearm. The zones of mechanical hyperalgesia to punctate and stroking stimuli and the region of flare were also mapped after the capsaicin injection. Heat pain thresholds inside the secondary mechanical hyperalgesic zone were not significantly different from thresholds outside the secondary mechanical hyperalgesia zone. In addition, pain ratings to an ascending series of heat stimuli delivered inside the zone of secondary hyperalgesia were not significantly different from pain ratings outside the zone of secondary hyperalgesia. Thus, there was no evidence for heat hyperalgesia within the zone of secondary hyperalgesia to punctate mechanical stimuli. Though the areas of punctate and stroking hyperalgesia were correlated, no correlation existed between the magnitude of capsaicin evoked pain and the areas mechanical hyperalgesia to punctuate and stroking stimuli or the area of flare. This suggests that independent mechanisms may mediate evoked pain, central sensitization that leads to mechanical hyperalgesia, and axon reflexive flare.

Cerebrospinal fluid adenosine deaminase activity for the diagnosis of tuberculous meningitis in children

Adenosine deaminase (ADA) activity was measured in the cerebrospinal fluid (CSF) of 27 subjects suffering from tuberculous meningitis (TBM), 19 from bacterial meningitis, 10 from encephalitis, and 10 control subjects. The mean CSF ADA level was significantly raised (P < 0.001) in TBM patients as compared to other study groups. A cut-off CSF ADA level of > 5 IU/1 was considered for the diagnosis of TBM, and the test had sensitivity and specificity of 89 and 92 per cent, respectively. Overall, it was found to be a better test in comparison to any other single test for the diagnosis of TBM. Confirmed TBM patients had significantly higher CSF ADA activity when compared with clinical TBM (P < 0.01) and the levels did not differ significantly among different stages of disease. The ADA level in TBM cases had significant correlation with CSF cell count (P < 0.01), lymphocyte percentage (P < 0.02) and protein concentration (P < 0.02). Thus, the CSF ADA activity assay was found to be a simple, useful and rapid diagnostic test for the early recognition of TBM in children.

The role of 5HT3 in nociceptive processing in the rat spinal cord: results from behavioural and electrophysiological studies

Recent studies have suggested that activity at different 5HT receptor subtypes in the spinal cord either inhibits or facilitates nociceptive processing in the spinal cord. The present study has examined the role of 5HT3 receptors in nociceptive processing in the dorsal horn of the rat spinal cord. Using both behavioural and electrophysiological studies, 5HT3 ligands have been applied by a common route (i.e. intrathecal microinjection). In addition, only noxious heat has been used as a form of stimulation. Intrathecal injection of mCPBG (0.02-0.2 nmol) increased the responsiveness of dorsal horn neurones to noxious stimulation. In contrast, two 5HT3 antagonists (ICS 205-930 (0.015-0.15 nmol) and GR 380032F (ondansetron 34 nmol)) reduced nociceptive responses. Using doses which influenced nociceptive neuronal responses no significant change in TFL was recorded. These findings suggest that activation at 5HT3 receptor facilitates nociceptive responses of some dorsal horn neurones; these results are discussed in relation to earlier reports concerning alternative effects.

The Drosophila engrailed and invected genes: partners in regulation, expression and function

We isolated and characterized numerous engrailed and invected alleles. Among the deficiencies we isolated, a mutant lacking invected sequences was viable and phenotypically normal, a mutant lacking engrailed was an embryo lethal and had slight segmentation defects, and a mutant lacking both engrailed and invected was most severely affected. In seven engrailed alleles, mutations caused translation to terminate prematurely in the central or C-terminal portion of the coding sequence, resulting in embryonic lethality and segmentation defects. Both engrailed and invected expression declined prematurely in these mutant embryos. In wild-type embryos, engrailed and invected are juxtaposed and are expressed in essentially identical patterns. A breakpoint mutant that separates the engrailed and invected transcription units parceled different aspects of the expression pattern to engrailed or invected. We also found that both genes cause similar defects when expressed ectopically and that the protein products of both genes act to repress transcription in cultured cells. We propose that the varied phenotypes of the engrailed alleles can be explained by the differential effects these mutants have on the combination of engrailed and invected activities, that engrailed and invected share a regulatory region, and that they encode redundant functions.

Expression of exon 3-retaining and -deleted human growth hormone receptor messenger ribonucleic acid isoforms during development

Recent investigations have suggested that human GH (hGH) and its receptor may have specific functions during human fetal life. To improve our understanding of the mechanisms of hGH action during gestation, we characterized the ontogenic appearance of hGH receptor messenger ribonucleic acid (mRNA) in multiple human fetal and postnatal tissues. Using RT-PCR assays, followed by Southern hybridization to confirm the specificity of the amplified fragments, we scanned the entire coding region of the hGH receptor mRNA. Transcription of the hGH receptor gene was observed in all fetal tissues studied (liver, kidney, skin, muscle, lung, adrenal, spleen, intestine, central nervous system, pancreas, and placental villi) from the earliest stage that could be examined [7-14.8 weeks fetal age (FA)]. Furthermore, we identified only 2 isoforms of the hGH receptor mRNA-coding region: exon 3 can be retained or deleted. Surprisingly, we found individual-specific, not tissue-specific, expression patterns of these two transcripts when we examined multiple tissues (n = 2-6) from 15 individuals (11.5-33 weeks FA); this individual-specific pattern of expression is maintained in cultured dermal fibroblasts for at least 12 generations (n = 2; 16 and 20 weeks FA). In addition, a cross-sectional study of 78 individuals (9 weeks FA to 43 yr postnatal age) showed that the exon 3-deleted transcript is predominantly expressed in tissues from fetuses of 9-20 weeks FA (P < 0.002). Finally, we showed that the absence of exon 3 from the mRNA is not due to genomic deletion of exon 3 by amplifying exon 3 from genomic DNA of 3 fetuses (13.3-19 weeks FA) expressing only the exon 3-deleted mRNA transcript. We conclude that 1) transcription of the hGH receptor gene occurs in multiple tissues as early as the first trimester of human fetal life; 2) the exon 3-retaining and -deleted transcripts are the only two isoforms of the hGH receptor mRNA-coding region during gestation; and 3) the pattern of expression of these transcripts is individual specific and may be developmentally regulated.

Properties of oligonucleosomes from active genes of rat liver

Active chromatin fraction from rat liver nuclei has been isolated under the lower ionic strength conditions, to prevent salt induced rearrangement and exchange of linker histone H1. Salt induced higher order folding in these oligonucleosomes was determined by sedimentation, viscosity, aggregation and circular dichroism studies. Sedimentation studies indicate that upon raising the ionic strength from 25 mM to 65 mM (mainly NaCl), active oligonucleosomes show intrafragmental interaction and formation of soluble oligomers. These oligomers disaggregate into unfolded monomers at 90 mM ionic strength. In contrast, oligonucleosomes from inactive genes show gradual increase in intrafragmental higher order folding without any interfragmental interaction on raising salt concentration. A much higher decrease in viscosity of active oligonucleosomes in comparison to bulk oligonucleosomes also support the above conclusion. However, on raising salt concentration above 100 mM NaCl, both the chromatin fractions are capable of forming insoluble aggregates. Decrease in the molar ellipticities of bulk oligonucleosomes at 273 and 282 nm is observed on raising ionic strength from 25 mM to 65 mM. A different pattern of this decrease is observed in case of active oligonucleosomes, indicating adaptation of a different type of salt induced secondary structure of DNA in these oligonucleosomes. Melting profile of DNA from active and bulk chromatin suggests that the base composition of both the chromatin fractions is same.

Creating a Drosophila wing de novo, the role of engrailed, and the compartment border hypothesis

Anterior/posterior compartment borders bisect every Drosophila imaginal disc, and the engrailed gene is essential for their function. We analyzed the role of the engrailed and invected genes in wing discs by eliminating or increasing their activity. Removing engrailed/invected from posterior wing cells created two new compartments: an anterior compartment consisting of mutant cells and a posterior compartment that grew from neighboring cells. In some cases, these compartments formed a complete new wing. Increasing engrailed activity also affected patterning. These findings demonstrate that engrailed both directs the posterior compartment pathway and creates the compartment border. These findings also establish the compartment border as the pre-eminent organizational feature of disc growth and patterning.

Cerebrospinal fluid adenosine deaminase activity and C-reactive protein in tuberculous and partially treated bacterial meningitis

Adenosine deaminase (ADA) activity measurement and C-reactive protein (C-RP) detection were done in CSF of 27 tuberculous meningitis (TBM) and 8 patients of partially treated bacterial meningitis, apart from routine biochemical tests. Both the groups had comparable CSF cell count, protein and sugar concentrations. The mean CSF ADA activity was significantly raised in TBM as compared to partially treated bacterial meningitis patients (p < 0.05). A cut-off ADA level < or = 5 IU/L and C-RP positively were used for differentiation of partially treated bacterial from TBM cases. Based on this, the sensitivity and specificity of ADA and C-RP were 62.5%, 88.9% and 75%, 100%, respectively. Since both the tests are simple and take lesser time to perform, they can be used as rapid diagnostic tests to remove diagnostic dilemma between the two diseases.

Neonatal meningitis: a 3-year retrospective study at the Mount Hope Women's Hospital, Trinidad, West Indies

The objective of this 3-year (1988-1990) retrospective study was to report the experience with neonatal meningitis at the Neonatal Intensive Care Unit, Mount Hope Women's Hospital, Trinidad, West Indies. Neonates were included in the study if organisms were cultured from the cerebrospinal fluid (CSF) and/or if there was a pleocytosis (> or = 100/mm3) in the CSF. There were 49 neonates with meningitis out of a total of 17,048 live born (LB) infants during the 3-year period to give an overall incidence of 2.87/1000 LB. This was five times higher than the incidence reported in the literature. There were an additional five who were outborns to give a total of 54 cases. There were 34 males (63 per cent) with a mean birth weight of 2389 g. Antenatal risk factors included preterm delivery (50 per cent), prolonged rupture of the amniotic membranes (37 per cent). Associated maternal conditions included hypertension and antepartum haemorrhage (9 per cent). In contrast to other reported studies, there was early onset of the condition (mean age at presentation was 4 days) and the commonest organism found was Group B streptococcus while the least common were the Gram-negative organisms. Also different in the present study was the high percentage (56 per cent) of meningitis associated with Group B septicaemia, the low mortality rate (13) and the low rate of neurological sequelae (40 per cent).

Adenosine deaminase activity in typhoid fever

Serum adenosine deaminase (ADA) activity was determined in 41 patients of typhoid fever and 15 normal controls. The mean ADA activity was significantly raised in typhoid fever patients as compared to controls (p < 0.001). The peak enzymatic activity was observed in the first week of illness. Complicated patients had lower mean ADA activity at diagnosis as compared to uncomplicated group and they showed a rise in enzyme level during defervescence, repeated in a few cases. A significant correlation between serum ADA activity and lymphocyte percentage was found (r = 0.4245, p < 0.001). It is concluded that ADA activity in typhoid fever patients not only indicates immunity but also has a prognostic value.

The actions of 5-HT1 agonists and antagonists on nociceptive processing in the rat spinal cord: results from behavioural and electrophysiological studies

We have developed a technique which allows drugs to be microinjected intrathecally intrathecally in anaesthetised rats whilst single unit recordings are made from dorsal horn neurones. Using this technique together with recordings of tail flick latency (TFL) elicited from lightly anaesthetised rats we have found that the specific 5-HT1a agonist 8-OH DPAT (15, 150, 300 nmol) increases nociceptive responses recorded from single dorsal horn neurones and decreases TFL. The non-specific 5-HT1b agonist TFMPP (300 nmol) and the general 5-HT1 agonist 5-CT (0.3, 3.0, 30 nmol) both decreased nociceptive responses and has inconsistent effects on TFL. Intrathecally applied 5-HT (130, 260 nmol) generally reduced nociceptive neuronal responses and increased TFL. In a minority of experiments, however, 5-HT increased nociceptive responses and it is suggested that this effect is associated with activation of 5-HT1a receptors. Activity at 5-HT1b receptors has the effect of suppressing or reducing responsiveness. The increased responsiveness of dorsal horn neurones to noxious stimulation associated with activity at 5-HT1a receptors may be associated either with increases in receptive field size, promotion of spinal nocifensive reflexes or the facilitation of the rostral transmission to specific brainstem sites.

Human maternal uniparental disomy for chromosome 16 and fetal development

Two severely growth-retarded fetuses found to have maternal uniparental disomy (UPD) for chromosome 16 and trisomy 16 placental mosaicism both had an unfavourable outcome. Antenatally, the first case was complicated by an unexplained raised maternal serum alpha-fetoprotein concentration, preterm premature rupture of the membranes, and growth retardation detectable at 21 weeks' gestation, whilst the other had an unexplained raised maternal serum human chorionic gonadotrophin level, a two-vessel cord on ultrasound, and cessation of growth at 25 weeks. At post-mortem, both babies had an imperforate anus. Fetal maternal UPD may explain the poor outcome that occurs in some cases of confined placental mosaicism for chromosome 16 and is also associated with specific fetal abnormalities.

Immunological approach for the identification of isozymes of CAM-stimulated phosphatase

Monoclonal antibodies are frequently used to identify protein isoforms. The present study documents certain artifacts in such applications and suggests methods for their testing. Two alpha subunit specific anti-calcineurin antibodies, VJ6 and VD3, reacted strongly with a brain isozyme, BPI, but not with the phosphatases from liver and spleen. Controlled proteolysis of BPI indicated that epitopes of both antibodies are localized to aminoterminal region, thus is suggesting that the lack of antibody reactivity could result from proteolytic artifacts. The occurrence of proteolysis during sample preparation can be monitored by including small quantity of BPI in the tissue extraction buffer. Rapid isolation procedure has been used to obtain liver and spleen isozymes reacting with VD3 but not VJ6 antibody.

Brain proline-directed protein kinase phosphorylates tau on sites that are abnormally phosphorylated in tau associated with Alzheimer's paired helical filaments

Brain proline-directed protein kinase (BPDK), which contains a catalytic subunit homologous to and displaying site-specific phosphorylation similar to p34cdc2 kinase (Lew, J., Winkfein, R. J., Paudel, H. K., and Wang, J. H. (1992) J. Biol. Chem. 267, 25922-25926), has been examined for possible involvement in tau phosphorylation. Immunoblot analyses using peptide antibodies specific for BPDK have revealed the presence of the kinase in bovine brain microtubules purified extensively by repeated polymerization and depolymerization cycles. When the microtubule proteins are separated into the tubulin and microtubule-associated protein fractions, BPDK is found exclusively in the latter fraction. BPDK phosphorylates both tau and MAP2, the former protein being phosphorylated to a stoichiometry of 3.8 mol of phosphate/mol of tau. Analysis of the phosphopeptides isolated from the tryptic digest of the phosphorylated bovine tau has revealed seven phosphorylation sites. Based on the sequence alignment between bovine and human tau proteins, these sites correspond to Ser-195, Ser-202, Thr-205, Thr-231, Ser-235, Ser-396, and Ser-404 of human tau. Mass spectrometric analysis of the tau protein isolated from Alzheimer's paired helical filaments (PHFs) has determined three abnormal phosphorylation sites and two phosphopeptides containing a total of five abnormal phosphates (Hasegawa, M., Morishima-Kawashima, M., Takio, K., Suzuki, M., Titani, K., and Ihara, Y. (1992) J. Biol. Chem. 267, 17047-17054). Two of the sites in tau phosphorylated by BPDK, Thr-231 and Ser-235, are among the abnormal phosphorylation sites, and the other sites phosphorylated by BPDK are within phosphopeptides from PHF-tau. These results suggest that BPDK may be one of the kinases responsible for the abnormal phosphorylation-associated PHF-tau.

Effect of pH adjustment of bupivacaine on onset and duration of epidural anaesthesia

The effect of pH adjustment of bupivacaine on onset and duration of sensory and motor block was studied in 45 patients undergoing lower abdominal and lower limb surgery. The study was done in 3 groups with the mean pH adjustment of 5.85, 7.14 and 7.21. Each patient was given 30 ml of 0.4% pH adjusted bupivacaine solution in epidural space. Onset of sensory block and duration were noticed by pin-prick method while motor block was observed by asking the patient to raise the thigh. It was observed that increase in pH of bupivacaine solution quickens the onset of sensory and motor block and increases the overall duration of neural blockade.

Isozyme-specific monoclonal antibodies of CaM-stimulated phosphatase: identification of an enzyme domain involved in metal ion activation

Bovine brain and lung extracts each contain three forms of CaM-stimulated phosphatase, designated BPI, BPII, and BPIII, and LPI, LPII, and LPIII, respectively. The different forms show uniform immunoreactivity toward one alpha subunit-specific monoclonal antibody, VD3, but differential reactivity toward another antibody, VJ6. Using the procedure of limited clostripain digestion, the binding sites for mAb VD3 and mAb VJ6 have been localized to the carboxylterminal region of about 40 amino acid residues and to the carboxylterminal one-third of the alpha subunit, respectively. The result has substantiated our previous suggestion that the isolated multiple forms of the brain and lung phosphatases represent isozymes rather than in vitro proteolysis artifacts. The effects of the two monoclonal antibodies on p-nitrophenylphosphatase activities of the bovine brain phosphatase isozymes have been examined. BPI and BPIII, the two VJ6 reactive brain isozymes, can be inhibited by VJ6 antibody in a metal ion and CaM-dependent manner; none of the isozymes are inhibited by mAb VD3. The inhibition of BPI by mAb VJ6 is most pronounced when the assay is carried out in the presence of CaM and Ni2+, whereas little or no effect is seen if Mg2+ plus Ca2+ are used as metal ion activators. Thus, VJ6 appears to identify an alpha-subunit domain important for the Ni(2+)-induced activation of CaM-stimulated phosphatase.

On Developing Optimal Process Capability Index

The process capability indices are used to assess the ability of a process to meet the present specification limits. These indices provide an easily understood qualification of a process performance. A fixed value for an ongoing process capability index is generally used. Minimization of statistical process control costs can be achieved by selecting an optimal process capability index. Presents a procedure to find an optimal ongoing process capability index.

Cutaneous thermal thresholds in patients with painful burning feet

Small nerve fibre sensory function was assessed by psychophysical estimates of cutaneous thermal thresholds in 30 patients who presented with the symptoms of painful burning feet. Thresholds were abnormal in 12 and normal in 18 patients although symptoms in the two groups were very similar. Various hypotheses for the mechanism of pain in small fibre neuropathy have been proposed previously and these are discussed, but the cause of symptoms in patients with normal thresholds, is unknown. The possibility exists that these patients have a neuropathic disorder which affects only those unmyelinated fibres involved with pain.

Resurgence of congenital syphilis in Trinidad

Twenty-eight cases of congenital syphilis (CS) were diagnosed shortly after birth at the Mount Hope Women's Hospital, Trinidad, during the period January 1985 to December 1988. The average annual incidence of CS was 115 per 100,000 live births, and the absolute number of cases and annual incidence doubled in the latter 2 years of the study. Diagnostic criteria used were a positive VDRL test in the 23 liveborn infants (100 per cent), signs suggestive of CS and confirmatory post-mortem findings. All mothers attended antenatal clinic at least once and 18 (64 per cent) were 25 years or younger. Only 17 (68 per cent) of the 25 gravidae with a positive VDRL test received treatment. Of 11 untreated gravidae, two did not have a VDRL test done, one had a negative VDRL test, three delivered before test results became known, one went into labour before going for treatment, and four (two of whom were substance abusers) did not comply with instructions to obtain treatment. There were five stillbirths and five neonatal deaths. There was no perinatal mortality when treatment was given earlier than 5 weeks before delivery, but mortality increased steeply if treatment was delayed or not given at all during pregnancy. Factors which contributed to this rise in the incidence of CS were an increased incidence of syphilis in females and failure to treat infected pregnant women.

Occurrence of diabetes mellitus after gestational diabetes mellitus in Trinidad

We undertook this study to determine the incidence of diabetes mellitus (DM) and impaired glucose tolerance (IGT) after gestational diabetes mellitus (GDM). It is a follow-up study of a consecutive sample of women with GDM in a tertiary care center in Trinidad, West Indies. The cohort was a consecutive sample of 157 women with GDM who delivered in the hospital between June 1981 and December 1984. Of these, a volunteer sample of 60 women (38%) consented to participate 3.5-6.5 yr later. The two groups were remarkably similar in ethnic composition, mean age at index delivery, marital status, and family history of DM. Interviews revealed that 26 women (43%) had already developed DM for which they were receiving treatment. The remaining 34 women (57%) were given a 2-h 75-g oral glucose tolerance test, and fasting and half-hourly venous blood samples were obtained and analyzed for plasma glucose. Based on accepted diagnostic criteria, 11 (32%) of 34 had DM, 10 (29%) had IGT, and 13 (38%) had normal glucose tolerance. A total of 37 (62%) of 60 women had developed DM, and another 10 (17%) had IGT in the intervening 3.5-6.5 yr. The results support findings that GDM is associated with an increased risk of mothers developing DM in later life.

Replacement of histone H1 by H5 in vivo does not change the nucleosome repeat length of chromatin but increases its stability

In vivo competition between histones H1 and H5 for chromatin has been studied in rat sarcoma XC10 cells transfected with a glucocorticoid responsive MMTV-H5 gene. Activation of H5 expression results in accumulation of H5 in the nuclei where it partially replaces H1. H5 displaces H1 from its primary binding sites presumably during chromatin replication and also binds with high affinity to secondary chromatin sites normally not occupied by H1. Replacement of H1 by H5 to levels similar to those of mature chicken erythrocytes does not alter the nucleosome repeat length of chromatin. This indicates that H5 is not solely responsible for the increase in nucleosome spacing of maturing erythroid cells. Exchange of H1 by H5 in vivo or in vitro results in a higher compaction/stability of chromatin.

A review of 36 babies with necrotizing enterocolitis

The clinical features, management, and outcome of 36 babies with necrotizing enterocolitis seen over 5 years at the Neonatal Unit, Mount Hope Women's Hospital, Trinidad, are described. The crude overall mortality rate was 25 per cent. The results suggest that prematurity, sepsis, and umbilical catheterization, but not enteral feeding or polycythaemia may be involved in the aetiology of this disease.

Patterns of engrailed protein in early Drosophila embryos

By the onset of gastrulation during nuclear cycle 14 of Drosophila embryogenesis, the engrailed gene is expressed in fourteen one-cell-wide stripes. Each stripe defines the anlagen of the posterior compartment of a metameric segment. We report here several observations relating to the role and disposition of the engrailed protein during the embryonic stages that precede cellularization. We demonstrate that in embryos mutant for the engrailed gene, there were characteristic morphological abnormalities as early as the 6th cleavage cycle. In addition, the engrailed protein was detected in pre-cycle-9 embryos by Western blot analysis. When localization of engrailed protein begins during cycle 14, engrailed expression was first present in broad anterior and posterior regions before the fourteen-stripe pattern appeared.

The extent of small fibre sensory neuropathy in diabetics with plantar foot ulceration

Thresholds for cutaneous warming and cooling stimuli were measured in 20 diabetics with neuropathic foot ulcers. All patients had a profound disturbance of sensory perception in the ulcerated foot with complete loss of perception of warming; thresholds for vibration and cooling were highly abnormal in all but two patients. Measurements of thermal threshold were made on both feet in 10 patients: warming was lost bilaterally in all, and cooling was bilaterally absent in six. There was no clear pattern of sensory loss in those diabetics with unilateral foot ulceration to suggest that sensory impairment was the determining factor for the development of a plantar ulcer. Measurements of thermal thresholds were made at additional sites in 13 patients and although the most marked abnormalities of sensation were always found in the feet, in some severe neuropaths, abnormal thresholds on the hand and even the face were demonstrated. Thresholds for warming were invariably more abnormal than thresholds for cooling. The diabetics with neuropathic ulceration in this study all had severe generalised peripheral nerve disease involving large myelinated as well as both small myelinated and unmyelinated sensory fibres. The quantitative evidence on the distribution of sensory loss for thermal sensations supports the hypothesis that the neuropathic process affecting the small myelinated and unmyelinated fibres is length dependent.

The conduction velocities of peripheral nerve fibres conveying sensations of warming and cooling

With the current practice of measuring thresholds for warming and cooling separately, the question of the exact nature of afferents subserving these sensations assumes new importance. Experiments to measure reaction times to warming and cooling stimuli at two sites on the lower limb are described. The conduction velocity for each sensation was estimated from the conduction distance and conduction time in the limb. The estimated mean conduction velocity for warming was 0.5, SD 0.2 m/s and cooling 2.1, SD 0.8 m/s. These figures confirm that the sensation of warming is conveyed in unmyelinated and cooling in small myelinated peripheral nerve fibres.

The value of testing for unmyelinated fibre, sensory neuropathy in diabetic impotence

Measurement of thermal thresholds provides a means of assessing neurological deficit and in particular of recognising a neuropathic process affecting unmyelinated and small myelinated fibres of the peripheral nerve. These groups of fibres cannot be tested by nerve conduction studies but are particularly susceptible to disease in diabetes. Thresholds for thermal sensation on the sole of the foot were measured in 33 men presenting with erectile dysfunction. All 15 men with erectile dysfunction, which had been considered on clinical grounds to be neuropathic, had abnormal thermal thresholds. Diabetics with non-neuropathic erectile dysfunction had normal results. Whereas tests of unmyelinated sensory fibre function were abnormal in all those with neuropathic erectile dysfunction, electrophysiological measurement of the bulbocavernosus reflex was normal in five of nine men with diabetic neuropathic impotence.

Placebo-controlled, double-blind evaluation of the efficacy and safety of yellow mercuric oxide in suppression of eyelid infections

We tested an over-the-counter ophthalmic ointment, yellow mercuric oxide 1%, for safety and efficacy in decreasing eyelid-margin bacterial-colony counts. Of 150 patients screened for high bacterial levels, 78 were randomized in double-blind fashion to either yellow mercuric oxide bid (41 patients or 53%) or a placebo (37 patients or 47%). Bacterial-colony counts were determined at outset and at days 4 and 7 of treatment. At the conclusion of treatment on day 7, 87% of patients in the mercuric oxide group were successful in decreasing bacterial counts, compared with 59% of patients treated with placebo (P = .01). Side effects were no higher in the active group than in the placebo group. We have shown mercuric oxide 1% to be safe and effective in reducing eyelid bacterial-colony counts in patients with hordeolum and blepharitis.

Binding of linker histones to the core nucleosome

Binding of chicken erythrocyte linker histones H1/H5 to the core nucleosome has been studied. Histones H1/H5 bind very efficiently to the isolated core nucleosome in vitro. The binding of linker histones to the core nucleosome is associated with aggregation of the particles. Approximately one molecule of linker histone binds per core nucleosome in the aggregates, irrespective of the concentration of the linker histones and the salt used. Histone H5 shows greater binding affinity to the core nucleosome as compared to H1. The carboxyl-terminal fragment of the linker histones binds strongly to the core nucleosome while the binding of the central globular domain is weak. Each core nucleosome is capable of binding two molecules of carboxyl-terminal fragment of linker histone. The core nucleosome containing one molecule of carboxyl-terminal fragment of linker histone requires higher salt concentration for aggregation while the core nucleosome containing two molecules of carboxyl-terminal fragment of linker histone can self-associate even at lower salt concentrations. On the basis of these results we are proposing a novel mechanism for the condensation of chromatin by linker histones and other related phenomena.

The transcription unit of the Drosophila engrailed locus: an unusually small portion of a 70,000 bp gene

Transcripts from the engrailed gene of Drosophila melanogaster have been characterized by Northern, S1 nuclease sensitivity, and primer extension analyses. The engrailed gene encodes three poly(A)+ transcripts (3.6 kb, 2.7 kb, and 1.4 kb) that derive from a 3.9-kb portion of the genome. No other transcribed regions were found up to 16 kb downstream and 48 kb upstream of the engrailed transcription unit, the portion of the genome to which engrailed mutations have been mapped. The structures of the engrailed transcripts are unaffected by lethal engrailed mutations that break the locus at points in the transcriptionally silent regions. Transcripts expressed by 145 kb of DNA that surround the engrailed locus were also identified by Northern analysis. In contrast to the large portion of the engrailed gene that is transcriptionally inactive, most of the surrounding regions are 10-fold more densely populated with transcripts. We presume that the unusually large silent region at the periphery of the engrailed transcription unit signify the presence of special mechanisms that regulate its expression.

A comparison of therapeutic bandage lenses, tarsorrhaphy, and antibiotic and hypertonic saline on corneal epithelial wound healing

Bandage lenses, a complete tarsorrhaphy, chloramphenicol 0.5%, and sodium chloride 2% were tested for their effect on corneal epithelial wound healing in rabbits. The healing rate was decreased with bandage lenses and increased by tarsorrhaphy. There was no significant effect on healing rate with either chloramphenicol or hypertonic saline.

The engrailed locus of D. melanogaster provides an essential zygotic function in precellular embryos

Early embryonic development in Drosophila depends on genes expressed during oogenesis or after zygote formation. We show that the engrailed gene is needed for the processes that organize the embryo during the nuclear divisions that precede cellularization. During the precellular blastoderm stages engrailed mutant embryos show several notable anomalies: the pole cells form at a position slightly displaced from the posterior pole; yolk nuclei continue to divide after the tenth nuclear division cycle, when wild-type yolk nuclei have stopped dividing mitotically; and somatic nuclei are not positioned uniformly along the embryo periphery and do not undergo mitotic divisions in regular waves. This early requirement for engrailed does not appear to be a maternal function, and only genetically engrailed embryos displayed these precellular phenotypes. Synthesis of a 2.7 kb poly(A)+ transcript of the engrailed region was found in precellular embryos.

Two cases of vallecular cyst presenting with acute stridor

Acute airway obstruction is a rare presentation of vallecular cysts in adults. In the two cases presented this probably reflected infection and responded well to a trial of conservative treatment.

Early maternal-child contact: effects on later behaviour

Fifty normal, healthy, full-term infants were allowed 45 minutes contact with their mothers immediately after birth at Victoria Jubilee Hospital, Kingston, Jamaica. The behaviour of these infants and their mothers was compared with matched controls at six and 12 weeks in a hospital follow-up interview. More early-contact mothers solely breast-fed their infants than did control mothers. Early-contact infants were less likely than controls to be restless or crying during the interviews. At 12 weeks, early-contact mothers were more likely than control mothers to rise and follow when their babies were taken from them, gazed more frequently at their infants, and were more likely to vocalise to their infants during the interview. These differences indicate that early contact promotes a closer relationship between a woman and her infant. Given the importance of breast-feeding as protection against gastro-enteritis and malnutrition, this closer relationship may be especially valuable in developing countries where such diseases are common.