Pycnotic cycle of the sex chromosome of Pyrgomorpha conica (Orthoptera) and development of spermiogenesis

We have analyzed the anomalous pycnotic cycle of the X sex chromosome of the grasshopper Pyrgomorpha conica throughout both meiotic divisions and its possible influence on spermiogenesis. During diplotene the sex chromosome shows two differentiated pycnotic regions: (i) the centromeric region, which is negatively heteropycnotic, and (ii) the noncentromeric region, which shows alternating negatively and positively heteropycnotic zones in all standard individuals. The variation in size and location of the negative heteropycnotic zones, their smooth appearance, and their lack of effect on spermiogenesis lead us to suggest that condensation differences and not euchromatinization are responsible for their presence. In two individuals the sex chromosome appeared partially isopycnotic at metaphase I, and high levels of abnormal spermatids (macrospermatids and microspermatids) were found. We suggest that the possible activity of this chromosome during the second meiotic division may promote the disruption of spermiogenesis by affecting the mechanism that maintains intercellular bridges between normal spermatids.

Arterial Hypertension, Metabolic Syndrome and Subclinical Cardiovascular Organ Damage in Patients with Asymptomatic Primary Hyperparathyroidism before and after Parathyroidectomy: Preliminary Results

Background. Primary hyperparathyroidism (PHPT) is associated with high cardiovascular morbidity, and the role of calcium and parathyroid hormone is still controversial. Objective. To evaluate the prevalence and outcomes of metabolic syndrome, hypertension, and some cardiovascular alterations in asymptomatic PHPT, and specific changes after successful parathyroidectomy. Material and Methods. We examined 30 newly diagnosed PHPT patients (8 males, 22 females; mean age 56 ± 6 yrs), 30 patients with essential hypertension (EH) (9 males, 21 females; mean age 55 ± 4), and 30 normal subjects (NS) (9 males, 21 females: mean age 55 ± 6). All groups underwent evaluation with ambulatory monitoring blood pressure, echocardiography, and color-Doppler artery ultrasonography and were successively revaluated after one year from parathyroidectomy. Results. PHPT patients presented a higher prevalence of metabolic syndrome (38%) with respect to EH (28%). Prevalence of hypertension in PHPT was 81%, and 57% presented altered circadian rhythm of blood pressure, with respect to EH (35%) and NS (15%). PHPT showed an important myocardial and vascular remodelling. During follow-up in PHPT patients, we found significant reduction of prevalence of metabolic syndrome, blood pressure, and "non-dipping phenomenon." Conclusions. Cardiovascular and metabolic alterations should be considered as added parameters in evaluation of patients with asymptomatic PHPT.

Progressive replacement of oral mucosa by conjunctiva in osteo-odonto-keratoprosthesis: preliminary observations

PURPOSE

In a Strampelli osteo-odonto-keratoprosthesis, a patch of oral mucosa is frequently used to cover the ocular surface after implantation of an osteodental lamina into the eye. In many cases, gross modifications in the eye covering become apparent a few years later. The aim of this study was to investigate the histologic findings in the clinically modified ocular surface.

METHOD

Biopsies were performed in 7 patients at the junction between the osteodental acrylic lamina and surrounding modified oral mucosa, during surgery for local plastic reconstruction or positioning of antiglaucoma silicone tubes. Specimens were examined by light microscopy.

RESULTS

Six of the 7 clinically modified specimens corresponded microscopically to conjunctiva. Typical oral mucosa could still be observed overlying the osteodental acrylic lamina.

CONCLUSIONS

The production of local regulatory factors is a possible explanation for the survival of oral mucosa over the osteodental acrylic lamina, whereas their absence in distant areas may have induced the oral mucosa to transdifferentiate into a conjunctival-type lining. Alternatively, conjunctival regrowth from forniceal stem cells should be taken into consideration.

Carvedilol titration in patients with congestive heart failure receiving inotropic therapy

BACKGROUND

Carvedilol has been shown to improve morbidity and mortality in patients with congestive heart failure (CHF). There are limited data of carvedilol use in patients on inotrope therapy. We present our experience with carvedilol titration in New York Heart Association (NYHA) class IIIb/IV patients stabilized on milrinone therapy, as a nonrandomized study with a parallel control group of patients never on inotropes. These patients achieved volume control and stabilization of their symptoms during the course of milrinone therapy.

METHODS AND RESULTS

Seventeen patients in class IIIb/IV CHF (group 1) on intermittent intravenous milrinone therapy and 15 patients in class II/IIIa compensated CHF (group 2) on standard triple heart failure therapy were titrated on carvedilol. Success and adverse events during titration were compared between the 2 groups. Fifteen (88%) patients in group 1 and 14 (93%) patients in group 2 were successfully titrated on carvedilol over 8.1 +/- 1.8 weeks and 6.7 +/- 2.8 weeks, respectively. The target dose of carvedilol (25 or 50 mg twice daily) was achieved in 13 (87%) patients (group 1) and 14 (93%) patients (group 2). Seven (47%) patients in group 1 and 4 (28%) patients in group 2 had adverse events during carvedilol titration. Eight (53%) patients in group 1 were weaned off milrinone over a period of 8.4 weeks after carvedilol titration, whereas the rest of the patients had reduction in the frequency of infusion. Ten (63%) patients in group 1 improved by one or more functional classes.

CONCLUSIONS

Patients in NYHA class IIIb/IV who are treated with inotropic therapy can be titrated on carvedilol after reaching a stable state while on milrinone and standard oral drugs. Most of these patients can be successfully weaned off of milrinone or have decreased frequency of infusions and demonstrate improved functional status. Prospective randomized trials are required to evaluate these observations made in a limited number of patients in class IIIb and IV CHF because the combination of milrinone and beta-blockers has never been adequately evaluated.

Protective antigens and mechanisms of anti-Candida immunity

Life threatening fungal diseases are now frequent in a substantial fraction of the immunocompromised host population. The toxicity and the relative scarcity of efficacious antifungal drugs highlight the need for developing alternative or integrative immunoprophylactic and therapeutic tools; among them the need to develop prophylactic or therapeutic vaccines against candidiasis, a widespread mucosal or deep-seated infection caused primarily by the fungus Candida albicans, are of clear priority. Vaccination is a highly beneficial medical practice, and probably the most cost-effective measure against disease onset and progression. It is based on the use of microbial antigens capable of conferring protection in a susceptible target host. To date, only a handful of Candida albicans antigens have been produced and very few of them have been thoroughly investigated for immunogenicity and protection in experimental models of candidiasis. Thus, approaches to the molecular, biochemical and functional characterization of novel C. albicans encoded molecules are most welcome to improve the perspective of developing in the near future an effective vaccine against C. albicans. Identification of anti-Candida vaccine candidates must take into account the diversity of Candida diseases, the various underlying mechanisms of protection as well as the major immune dysfunctions observed as predisposing factors for disease. Antigens to be considered possible vaccine candidates include members of the aspartyl proteinase (Sap2) family and the 65kDa mannoprotein (MP65) antigen. An additional molecule of C. albicans which has not yet been identified but deserves great consideration as a vaccine candidate is the yeast-killer toxin receptor (KTR). Initial experimental evidence strongly suggests that the above antigens are able to elicit protective immunity against mucosal and/or systemic candidiasis. A series of molecular, biochemical and immunological studies aimed at validating and strengthening this initial evidence are in progress, with the ultimate goal of producing recombinant or natural antigens that can be assessed for their ability to elicit a protective immunity in animal models and the mechanisms whereby protection is achieved, with emphasis on determination of immune correlates of protection.

Ursodeoxycholic acid administration in patients with cholestasis of pregnancy: effects on primary bile acids in babies and mothers

Little is known about the effects on the fetus of ursodeoxycholic acid (UDCA) treatment for intrahepatic cholestasis of pregnancy (ICP). Twenty ICP patients were given UDCA at 1.5 to 2 g/d, to our knowledge the highest dosage yet reported. Effects were evaluated on conjugated bile acids (BA) in amniotic fluid (15 of 20 patients) and umbilical cord serum obtained at delivery (20 of 22 newborns), as compared with 10 untreated patients (amniotic fluid, 9 of 10 patients; cord serum, 9 of 10 newborns). Liver function tests, serum BA and UDCA were evaluated on enrollment and then weekly until 1 week after delivery. Maternal serum conjugated cholic (CCA) and chenodeoxycholic (CCDCA) acids levels fell (18.5 +/- 1.9 to 10.5 +/- 1.9 micromol/L, and 5.8 +/- 0.8 to 2.97 +/- 0.7 micromol/L, respectively [P <.01]) in treated patients, and remained unaffected (20.0 +/- 3.1 vs. 20.3 +/- 2.3, and 5.6 +/- 0.6 vs. 5.4 +/- 0.5, respectively [P = not significant]) in untreated ones. Serum conjugated UDCA levels rose to 16.5 +/- 1.8 micromol/L (P<.001). Median values of CCA and CCDCA in amniotic fluid around delivery were 4.9 +/- 12.4 and 4.8 +/- 7.7 micromol/L, respectively, in treated patients, as against 17.9 +/- 27.5 and 18.5 +/- 20.9 micromol/L in untreated ones. In treated mothers, CCA and CCDCA concentrations in cord blood were 6.0 +/- 0.9 and 5.2 +/- 0.95 micromol/L, respectively, as against 21.9 +/- 5.6 and 18.9 +/- 2.1 micromol/L in untreated ones. In treated patients, median UDCA values in amniotic fluid and cord blood were 0.8 +/- 2.4 and 0.9 +/- 0.14 micromol/L, respectively. We conclude that increasing the dose of UDCA more effectively controls ICP and improves maternal clinical outcome after delivery.

Xkid, a chromokinesin required for chromosome alignment on the metaphase plate

Metaphase chromosome alignment is a key step of animal cell mitosis. The molecular mechanism leading to this equatorial positioning is still not fully understood. Forces exerted at kinetochores and on chromosome arms drive chromosome movements that culminate in their alignment on the metaphase plate. In this paper, we show that Xkid, a kinesin-like protein localized on chromosome arms, plays an essential role in metaphase chromosome alignment and in its maintenance. We propose that Xkid is responsible for the polar ejection forces acting on chromosome arms. Our results show that these forces are essential to ensure that kinetochores and chromosome arms align on a narrow equatorial plate during metaphase, a prerequisite for proper chromosome segregation.

Phosphorylated proteins are involved in sister-chromatid arm cohesion during meiosis I

Sister-chromatid arm cohesion is lost during the metaphase I/anaphase I transition to allow homologue separation. To obtain needed information on this process we have analysed in grasshopper bivalents the sequential release of arm cohesion in relation to the behaviour of chromatid axes. Results show that sister axes are associated during early metaphase I but separate during late metaphase I leading to a concomitant change of chromosome structure that implies the loss of sister-kinetochore cohesion. Afterwards, homologues initiate their separation asynchronously depending on their size, and number and position of chiasmata. In all bivalents thin chromatin strands at the telomeres appeared as the last point of contact between sister chromatids. Additionally, we have analysed the participation of phosphoproteins recognised by the MPM-2 monoclonal antibody against mitotic phosphoproteins in arm cohesion in bivalents and two different kinds of univalents. Results show the absence of MPM-2 phosphoproteins at the interchromatid domain in mitotic chromosomes and meiotic univalents, but their presence in metaphase I bivalents. These phosphoproteins are lost at the onset of anaphase I. Taken together, these data have prompted us to propose a ‘working’ model for the release of arm cohesion during meiosis I. The model suggests that MPM-2 phosphoproteins may act as cohesive proteins associating sister axes. Their modification, once all bivalents are correctly aligned at the metaphase plate, would trigger a change of chromosome structure and the sequential release of sister-kinetochore, arm, and telomere cohesions.

Outpatient infusion clinics: a strategy for the successful management of advanced heart failure

During the past four years, the Heart Failure Unit a Columbia Michael Reese Hospital and Medical Center in Chicago has used outpatient intermittent low-dose inotropic therapy to improve care and quality of life while reducing the number of hospital admissions, decreasing lengths of stay, and lowering the number of emergency room visits.

The osmium tetroxide-p-phenylenediamine procedure reveals the chromatid cores and kinetochores of meiotic chromosomes by light and electron microscopy

We analyzed first-metaphase meiotic chromosomes of the grasshopper Chorthippus jucundus by two different methods, i.e., a silver impregnation technique and the osmium tetroxide-p-phenylenediamine (Os-PPD) procedure. The former was applied on squashed testes previously fixed in ethanol-acetic acid, whereas for Os-PPD the material was not subjected to any previous extraction treatment but was fixed in OsO4, treated with PPD, and embedded in Epon 812. Both techniques revealed chromatid cores and kinetochores regardless of the processing of the material (squashed or sectioned). Unstained Os-PPD sections were analyzed by light microscopy and transmission electron microscopy (TEM). The Os-PPD technique provided a high contrast of chromatid cores and kinetochores in relation to the chromatin, which revealed a low electron density. To determine the Os-PPD reaction mechanism, the PAS procedure, as well as scanning electron microscopy (SEM) backscattering and SEM X-ray microanalysis, was performed on sections. By use of the Os-PPD-PAS procedure, glycol groups formed by oxidation of osmium bound to aromatic substrates were detected in chromatid cores and kinetochores by brightfield and fluorescence microscopy. A high Z contrast was detected in these structures by backscattered electron imaging. SEM X-ray microanalysis showed osmium and phosphorus to be the main elements present on the chromatid cores. Taking into account the known reactivity of OsO4 and the present results, the possible participation of nucleic acids as well as proteins in the Os-PPD reaction mechanism and in the composition of chromatid cores and kinetochores is discussed.

Meiosis in holocentric chromosomes: kinetic activity is randomly restricted to the chromatid ends of sex univalents in Graphosoma italicum (Heteroptera)

We have determined the number and location of the nucleolar organizing regions in spermatocytes of Graphosoma italicum (2n = 12A + XYmale/XXfemale) by means of silver impregnation, chromomycin A3/distamycin A staining and fluorescence in situ hybridization. The identification of only one nucleolar organizing region located at one of the X chromosome ends has provided a suitable cytological marker to analyse the segregation of this univalent and that of the XY pseudobivalent during the first and second meiotic divisions respectively. Our results clearly show that at first meiotic metaphase the chromatids of the X chromosome are orientated with their long axes perpendicular to the polar axis. Although the kinetic activity is restricted to only one end in both X chromatids during the first meiotic division, both ends of the same chromatid have the same probability of showing such kinetic activity. In this sense, we also report that the chromatid segregation may be initiated either at the same sister chromatid ends or at opposite ends in each chromatid. Thus, this indicates a sex chromatid independence as regards to the chromatid segregation during the first meiotic division. Throughout the second meiotic division both ends of the X chromatid are involved with the same probability in the end-to-end association to conform the XY pseudobivalent. This also implies a random localization of the kinetic activity at the ends opposite to those involved in the end-to-end association.

Nucleolar cycle and localization of NORs in early embryos of Parascaris univalens

During early embryogenesis of the nematode Parascaris univalens (2n=2) the processes of chromatin diminution and segregation of the germ and somatic cell lineages take place simultaneously. In this study we analyzed the nucleolar cycle in early embryos, both in germinal and somatic blastomeres, by means of silver staining and antibodies against the nucleolar protein fibrillarin. We observed an identical nucleolar cycle in both types of blastomeres, hence, the chromatin diminution process has no effect on the nucleolar cycle of somatic blastomeres. We report the existence of outstanding differences between this cycle and those previously reported during early embryogenesis of other species. There is a true nucleolar cycle in early embryos that shows a peculiar nucleolar disorganization at prophase, and a preferential localization of prenucleolar bodies only on the euchromatic regions during nucleologenesis. Moreover, fibrillarin does not form a perichromosomal sheath in metaphase or anaphase holocentric chromosomes, probably owing to their special centromeric organization. The number and location of nucleolus organizer regions (NORs) in the chromosomal complement have been determined using silver impregnation, chromomycin A3/ distamycin A staining, and fluorescent in situ hybridization using an rDNA probe. There are only two NORs, one per chromosome, and these are located in the middle of the euchromatic central regions. This location implies that no rDNA sequences are lost in blastomeres after chromatin diminution. Moreover, the constant presence of two nucleoli in somatic blastomeres suggests that NORs are not affected during the fragmentation of euchromatic regions when this process occurs.

Effectiveness of adjunctive treatment with steroids in reducing short-term mortality in a high-risk population of children with bacterial meningitis

Bacterial meningitis is still an important cause of death and/or persistent nervous system damage in children living in developing countries. The aim of the study was to evaluate the effectiveness of steroids in reducing mortality and neurologic sequelae in children affected by bacterial meningitis within the context of a developing country (Mozambique), where the case-fatality rate of this disease is over 30 per cent. Seventy children with bacterial meningitis were randomized to receive either conventional antibiotic therapy or antibiotic therapy plus dexamethasone. On hospital admission there were no statistically significant differences between the two groups with regard to clinical and laboratoristic features. When dexamethasone was used early mortality, within 24 h, was significantly reduced (1/34 v. 8/36, P < 0.05). Total mortality among steroid treated patients, including those who were comatose on admission, was also reduced even if the difference did not reach statistical significance. A favourable trend in terms of fewer serious neurologic abnormalities was also observed among survivors in the steroid treated patients (5/26 v. 7/24). Fever and CSF abnormalities also disappeared more rapidly in patients receiving dexamethasone (P < 0.05). This study showed that the beneficial effect of adjunctive steroid therapy in children with bacterial meningitis can be even more important in areas where the case-fatality rate of this disease is still very high.

Supernumerary heterochromatic segments associated with the nucleolar chromosomes of Pyrgomorpha conica (Orthoptera) contain methylated rDNA sequences

The two nucleolus organizing chromosome pairs of the grasshopper Pyrgomorpha conica can carry a proximal supernumerary heterochromatic segment. We employed different cytological techniques to characterize and analyze the possible origin of this segment. The supernumerary segment and the nucleolus organizing regions (NORs) show similar responses after C-banding plus either Giemsa or acridine orange, and chromomycin A3/distamycin A staining to detect GC-rich chromosome regions. Fluorescence in situ hybridization with a biotinylated rDNA probe demonstrated that the segment originated by amplification of the rDNA genes. However, as the silver staining indicates, the ribosomal genes present in the segment are not active since no nucleolus is formed. The use of in situ digestion with the isoschizomeric MspI and HpaII restriction endonucleases and subsequent Giemsa, ethidium bromide or chromomycin A3/distamycin A staining, suggests that the segment has been inactivated by DNA methylation.

Acute stabilization of the cervical spine by halo/vest application facilitates evaluation and treatment of multiple trauma patients

The management of acute cervical spine injuries has traditionally used bed-based skeletal traction until all non-neurologic injuries have been evaluated. This treatment method substantially hinders the ability to transport patients and to perform imaging studies and surgical procedures. In contrast, early application of a halo/vest apparatus provides immediate cervical stabilization and facilitates the diagnostic work-up and treatment of the patients with multiple injuries. The records of all 78 patients admitted from February 1988 through June 1991 who had acute cervical spine fractures, subluxations, or both with a risk of instability were reviewed. All patients were treated with halo/vests and no patient deteriorated neurologically following halo/vest application. Twenty-nine patients (37%) had a total of 55 associated injuries including long bone/pelvic fractures in 17, thoracic injuries in 13, closed head injuries in 11, facial fractures in 6, noncontiguous spinal fractures in 5, and abdominal injuries in 3. The mean injury Severity Score (ISS) was 18 (range, 9-54). While in the halo/vest, 43 patients (55%) had a total of 99 diagnostic studies completed and 46 patients (59%) had a total of 76 surgical procedures performed. There were 35 neurosurgical procedures on 32 patients and 41 non-neurosurgical surgical procedures on 24 patients. Over the past year, 20 of 21 patients (95%) had their halo/vest placed in the emergency department. The data demonstrate that many diagnostic and surgical procedures need to be performed on patients with unstable cervical spine injuries.(ABSTRACT TRUNCATED AT 250 WORDS)

Involvement of chromatid cohesiveness at the centromere and chromosome arms in meiotic chromosome segregation: a cytological approach

Kinetochores and chromatid cores of meiotic chromosomes of the grasshopper species Arcyptera fusca and Eyprepocnemis plorans were differentially silver stained to analyse the possible involvement of both structures in chromatid cohesiveness and meiotic chromosome segregation. Special attention was paid to the behaviour of these structures in the univalent sex chromosome, and in B univalents with different orientations during the first meiotic division. It was observed that while sister chromatids of univalents are associated at metaphase I, chromatid cores are individualised independently of their orientation. We think that cohesive proteins on the inner surface of sister chromatids, and not the chromatid cores, are involved in the chromatid cohesiveness that maintains associated sister chromatids of bivalents and univalents until anaphase I. At anaphase I sister chromatids of amphitelically oriented B univalents or spontaneous autosomal univalents separate but do not reach the poles because they remain connected at the centromere by a long strand which can be visualized by silver staining, that joins stretched sister kinetochores. This strand is normally observed between sister kinetochores of half-bivalents at metaphase II and early anaphase II. We suggest that certain centromere proteins that form the silver-stainable strand assure chromosome integrity until metaphase II. These cohesive centromere proteins would be released or modified during anaphase II to allow normal chromatid segregation. Failure of this process during the first meiotic division could lead to the lagging of amphitelically oriented univalents. Based on our results we propose a model of meiotic chromosome segregation. During mitosis the cohesive proteins located at the centromere and chromosome arms are released during the same cellular division.(ABSTRACT TRUNCATED AT 250 WORDS)

Neonatal and post-neonatal onset of early congenital syphilis: a report from Mozambique

Congenital syphilis (CS) has been and continues to be a principal public health problem in developing countries. Despite the wide experience acquired, physicians still have problems in diagnostic evaluation. We report 145 cases of CS at the Central Hospital, Maputo, emphasizing the differences in clinical features and in the results of serological and X-ray examinations between the neonatal and post-neonatal age groups. In the post-neonatal age group, the clinical expression of CS is mostly overt. It is commonly recognized that manifestations of CS in the neonatal age group are often poor or negative, yet a relevant percentage of CS that we report were fully symptomatic. In the neonatal age, the Venereal Disease Research Laboratory (VDRL) test in the mother and characteristic osteochondritic lesions on X-ray examination of the long bones help to make the diagnosis; in the post-neonatal age group, the VDRL test in the child is more often positive than in the mother and X-ray examination shows most periostitic lesions.