Membrane partition coefficients chromatographically measured using immobilized artificial membrane surfaces

Immobilized artificial membranes (IAMs) are chromatographic surfaces prepared by covalently immobilizing cell membrane phospholipids. IAM surfaces mimic fluid cell membranes. Solute capacity factors (k'IAM) measured on IAM columns correlate very well with solute equilibrium partition coefficients (Km') measured in fluid liposome systems. For 23 structurally unrelated compounds, log-(k'IAM) correlates with log(Km') with a linear correlation coefficient r = 0.907. This indicates that solute partitioning between the IAM bonded phase and the aqueous mobile phase is similar to the solute partitioning between liposomes and the aqueous phase. Although both IAM chromatography and liposome partitioning can be used as in vitro methods to predict solute partitioning into cell membranes, IAM chromatography is experimentally convenient compared to liposome systems. To study the effect of lipid structure on drug binding to IAMs, IAMs were prepared from three different phosphatidylcholine ligands: (i) a diacylated phosphatidylcholine ligand, (ii) a single chain ether phosphatidylcholine ligand, and (iii) a single chain phosphatidylcholine ligand that lacks a glycerol backbone. Solute retention data were identical for all of these IAMs, and consequently, predictions of solute binding to fluid membranes were also identical. This indicates that the structure of the phosphatidylcholine ligand that is immobilized is not critical for the binding of solutes. Since the structure is not important, the binding of solutes to membranes is a bulk phase property, i.e., it is the interface created by the ligands that determines the solute binding properties, not the ligands themselves. Solute partitioning using octanol/water systems does not correlate with k'IAM unless a homologous series of hydrophobic solutes is being evaluated.

Evidence that brain nitric oxide synthase is the major nitric oxide synthase isoform in the hypothalamus of the adult female rat and that nitric oxide potently regulates hypothalamic cGMP levels

Recent studies suggest that nitric oxide (NO) may function as a neurotransmitter in the hypothalamus. In order to provide further evidence supporting this contention, we examined: (1) whether the hypothalamus displays significant NO synthase (NOS) activity and whether the activity is inhibited by an NOS inhibitor, (2) whether the different NOS isoforms [brain (b)-NOS, endothelial (e)-NOS and macrophage (m)-NOS] are expressed in the various nuclei of the hypothalamus of the random cycling adult female rat, (3) whether the NO donor molecule, sodium nitroprusside (SNP), regulates the heme-containing enzyme, guanylate cyclase in the preoptic area and medial basal hypothalamus of the random cycling adult female rat as well as the ovariectomized steroid (estradiol-17 beta)-treated rat. The results of the study showed that the preoptic area (POA) and medial basal hypothalamus (MBH) of the adult female rat displays significant NOS activity which can be dose-dependently inhibited by an NOS inhibitor. All three NOS isoform mRNA transcripts were present in the hypothalamus, with the order of expression being b-NOS > e-NOS > m-NOS. Immunohistochemical localization using monoclonal antibodies to the specific NOS isoform proteins revealed that b-NOS represented the major form of NOS in the hypothalamus based on density and distribution of immunostaining. b-NOS immunostaining was especially dense in the organum vasculosum laminae terminalis (OVLT), medial preoptic area (MPOA), supraoptic nucleus, and moderately dense in the arcuate nucleus/median eminence. The pattern and density of b-NOS staining closely mirrored our previously reported pattern of NADPH-diaphorase staining in the hypothalamus, and a polyclonal antibody to b-NOS yielded a similar staining pattern as that observed for the monoclonal antibody. In contrast to the dense staining observed for b-NOS in the hypothalamus, we observed no specific staining for m-NOS in the hypothalamus. e-NOS immunostaining, on the other hand, was present in the hypothalamus, but to a much lesser extent than b-NOS. Light e-NOS staining was observed in the OVLT, MPOA, supraoptic nucleus and arcuate nucleus/median eminence. That NO can regulate guanylate cyclase as a potential mediator of its effects was demonstrated using SNP which dose-dependently elevated cGMP levels in the POA and MBH of random cycling rats and estrogen-primed ovariectomized rats. The effect of SNP was due to its NO donor ability as it was blocked by the NO scavenger molecule, hemoglobin. Interestingly, hemoglobin alone caused a 50-60% reduction in basal cGMP levels, suggesting that endogenously produced NO regulates basal guanylate cyclase activity. Taken as a whole, the present study demonstrates that b-NOS is the major NOS isoform in the hypothalamus and it also provides evidence that cGMP may be a mediator of NO effects in the female hypothalamus as evidenced by the potent ability of SNP to elevate cGMP levels in the POA and MBH.

Seroprevalence of human herpesvirus 8 among Zambian women of childbearing age without Kaposi's sarcoma (KS) and mother-child pairs with KS

The seroprevalence of human herpesvirus 8 (HHV-8) among a group of Zambian women of reproductive age and among mother-child pairs in which either one of them has Kaposi's sarcoma (KS) was determined. A cross-sectional group of 378 pregnant women was randomly recruited into the study, and 183 (48.4%) had HHV-8 antibodies. Among the human immunodeficiency virus (HIV)-1-infected women, 51.1% were HHV-8-seropositive, whereas of HIV-1-negative women, 47.3% were HHV-8-seropositive. In addition, 21 women index patients with KS and 5 young children index patients with KS were studied. All children with KS had mothers who were HHV-8-seropositive, while not all children whose mothers had KS were infected with HHV-8. Our study suggests that there is a high HHV-8 seroprevalence among Zambian women, and the rate is almost the same in HIV-1-positive and -negative women. This high seroprevalence may be a contributing factor toward the increased frequency of KS in this population.

Seroprevalence of human immunodeficiency virus type 1 infection in Zambian children with tuberculosis

Descriptions in the medical literature of human immunodeficiency virus type 1 (HIV-1) in children with tuberculosis (TB) are scanty. This study determined the seroprevalence of HIV-1 in 237 hospitalized children between the ages of 1 month and 14 years with a clinical diagnosis of TB (125 males and 112 females) and in 242 control children (149 males and 93 females). The overall HIV-1 seroprevalence rate in patients with TB was 37% (88 of 237) compared with 10.7% (26 of 242) among the control group (P < 0.00001: odds ratio 5.37, 95% confidence interval = 3.21 < 5.37 < 9.47). HIV-1 seropositivity in children with TB ranged from 53% (31 of 58) in the 12- to 18-month age group to 14% (9 of 61) in the 10- to 14-year-olds. The risk of TB attributable to HIV infection was 29%. The predominant clinical presentation in both seronegative (84.6%) and seropositive (89.7%) groups was that of pulmonary TB and there were no significant differences in clinical presentation between the two groups of patients. Only 54.8% of the patients attended follow-up clinics regularly whereas 32% were lost to follow-up within 3 months. Bacillus Calmette-Guérin vaccination coverage was 87.3% among TB patients and 90.5% in the controls. No significant differences in B. Calmette-Guérin vaccination rates between the seronegative and seropositive children were seen. Coinfection with HIV and TB in children is now one of the major public health problems in Zambian children.

Dysregulated biomarkers induce distinct pathways in preterm birth

OBJECTIVE

To document racial disparity in biomarker concentrations in maternal/fetal plasma and amniotic fluid between African Americans and European Americans with spontaneous preterm birth (PTB; cases) and normal term birth (controls), and their contribution to distinct pathophysiological pathways of PTB.

DESIGN

Nested case-control study.

SETTING

The Perinatal Research Center, Nashville, Tennessee, USA.

SAMPLE

Maternal and fetal plasma and amniotic fluid samples were collected from 105 cases (59 African American and 46 European American) and 86 controls (40 African American and 46 European American).

METHODS

Thirty-six biomarkers were analysed using the protein microarray approach.

MAIN OUTCOME MEASURES

Differences in biomarker concentrations between cases and controls of different races in maternal, fetal and intra-amniotic compartments, and the risk of PTB. Dysregulated biomarker-induced PTB pathways associated with PTB in each race were determined using ingenuity pathway analysis (IPA).

RESULTS

Racial disparity was observed in biomarker concentrations in each compartment between cases and controls: amniotic fluid, IL8 and MIP1α differed between case and controls in European Americans, whereas ANGPT2, Eotaxin, ICAM-1, IL-1β, IL1RA, RANTES and TNFα differed between case and controls in African Americans. In both races the FAS ligand, MCP-3 and TNFR-I differed between cases and controls. For fetal plasma, ANGPT2, Eotaxin, FGF basic, ICAM-1, IGF-I, IL10, IL-1β, IL2, IP10 KGF, MCP-3, MIP1α, PDGF-BB, TGFα, TGFβ1, TIMP1, TNFα, TNFR-I, TNFR-II and VEGF differed between cases and controls in European Americans, whereas only MMP7 differed between cases and controls in African Americans. IL-8 differed between cases and controls in both races. For maternal plasma, IL1RA, MMP7 and VEGF differed between cases and controls in European Americans, whereas ANGPT2, FGF basic, IL-1β, IL5, IL6R, KGF, MCP-3, MIP1α, TIMP1 and TNFα differed between cases and controls in African Americans. ANG, IL8 and TNFR-I differed between cases and controls in both races.

CONCLUSIONS

We conclude that: (1) biomarker concentrations in maternal, fetal and intra-amniotic compartments differ between cases and controls; (2) there is racial disparity in the biomarker profile in each of the compartments; (3) substantial numbers of dysregulated fetal plasma biomarkers contribute to PTB in European Americans, whereas maternal plasma biomarkers contribute to PTB in African Americans; and (4) both inflammation and haematological functions are associated with PTB in European Americans, but maternal proinflammatory changes dominate PTB in African Americans. Biomarker analyses document racial disparity and the distinct pathophysiological contributions from different compartments that can determine pregnancy outcome.

Cutaneous hypersensitivity reactions due to thiacetazone in the treatment of tuberculosis in Zambian children infected with HIV-I

Tuberculosis is one of the most common infections in Zambian adults and children infected with HIV. In Africa, cutaneous hypersensitivity reactions attributed to thiacetazone during treatment of tuberculosis in adults infected with HIV-I have been well documented. This study monitored adverse drug reactions during treatment for tuberculosis over an 18 month period (1 April 1990 to 31 October 1991) in 237 children with a clinical diagnosis of tuberculosis (125 boys and 112 girls; 88/237 (37%) infected with HIV-I) and 242 control children (149 boys and 93 girls; 26/242 (11%) infected with HIV-I). Twenty two (9%) of the 237 children with tuberculosis developed hypersensitivity skin reactions during the course of treatment. Adverse skin reactions were seen more often in children infected with HIV than in those who were not (odds ratio 11.65, 95% confidence interval 3.07 to 34.88). These represented 19 (21%) of 88 children infected with HIV and three (2%) of 149 children not infected with HIV. These skin reactions occurred after a period of treatment ranging between two and four weeks among 14 children receiving the HST (isoniazid, streptomycin, thiacetazone) regimen and eight children receiving the HSTR (isoniazid, streptomycin, thiacetazone, rifampicin) regimen. Twelve (55%) of the 22 children who reacted adversely to treatment developed the Stevens-Johnson syndrome. All 12 of these children with the Stevens-Johnson syndrome were infected with HIV. The mortality among these children who developed the Stevens-Johnson syndrome was 91% (11 of 12 died within three days of the onset of the reaction). No further reactions were observed in the 11 children who recovered from the cutaneous hypersensitivity reactions after thiacetazone was discontinued over a period of six months of further treatment of tuberculosis. The results of this study were in part responsible for the recommendations put forward by the World Health Organization to avoid the use of thiacetazone in the treatment of tuberculosis in children infected with HIV.

Evidence for a physiological role for nitric oxide in the regulation of the LH surge: effect of central administration of antisense oligonucleotides to nitric oxide synthase

Antisense oligonucleotides of brain-nitric oxide synthase (b-NOS) and endothelial-NOS (e-NOS) were used in steroid-primed ovariectomized rats to examine the physiological role of nitric oxide in the regulation of the LH surge. Since macrophage-NOS (m-NOS) is not produced in the hypothalamus under normal conditions, the m-NOS antisense oligonucleotide was used as control for the possible toxicity of the phosphorothioated and propynylated antisense oligonucleotides used. Female rats were ovariectomized on day 70 of age and implanted with a third ventricle cannula on day 77 of age, injected with 5 micrograms of estradiol on days 84 and 85 of age at 17.00 h and with 1 mg progesterone or vehicle on day 86 at 09.00 h. Blood samples were collected between 13.00 and 19.00 h on day 86 of age via a jugular cannula inserted on day 85 of age. Antisense oligonucleotides (400 or 800 ng) or vehicle were injected in the third ventricle at 17.00 h on days 84 and 85 just before the estradiol injection and at 06.00 and 12.00 h on day 86. Neither the 400-ng nor the 800-ng dose of m-NOS AS had any effect on the steroid-induced LH surge. In contrast, central administration of the 400-ng dose of e-NOS AS and the 800-ng dose of b-NOS AS significantly attenuated the steroid-induced LH surge. The 40% reduction in LH by e-NOS AS and b-NOS AS was accompanied by a 33 and 28% reduction in their respective protein levels as shown by Western blots. The higher amount of b-NOS AS needed to reduce the LH surge is probably due to the high abundance of b-NOS in the hypothalamus as compared to e-NOS. As a whole, this study provides significant evidence for a physiological role of nitric oxide in mediating the steroid-induced LH surge.

Vertical transmission of Kaposi's sarcoma-associated herpesvirus

Little is presently known about the specific routes of transmission of Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus-8 (HHV-8). To investigate whether this agent might be transmitted vertically from mother to infant, we conducted a study on 89 KSHV seropositive mothers and their newborn infants. Thirteen mothers (14.6%) had KSHV DNA detected in their peripheral blood mononuclear cells (PBMC). Two of 89 samples drawn at birth from infants born to KSHV seropositive mothers had KSHV DNA detectable within their PBMC. These findings suggest that KSHV can be transmitted perinatally, but infrequently. Other routes of transmission such as horizontal transmission remain the most likely means of KSHV transmission.

Human immunodeficiency virus type-1 infection in Zambian children with tuberculosis: changing seroprevalence and evaluation of a thioacetazone-free regimen

SETTING

This study was conducted at the Department of Paediatrics and Child Health, University Teaching Hospital (UTH), in Lusaka, Zambia.

OBJECTIVES

To monitor the seroprevalence of HIV type-1 in children with tuberculosis and to evaluate the response to anti-tuberculosis therapy using a thioacetazone-free treatment regimen.

DESIGN

A prospective cross-sectional study of all consecutive newly diagnosed cases of TB in children from 1 month-15 years of age seen at the University Teaching Hospital (UTH) in Lusaka, Zambia between 1 October 1991 and 31 May 1992.

RESULTS

120 children with a clinical diagnosis of tuberculosis and 167 controls were enrolled in the study. The overall HIV type-1 seroprevalence rate in children with tuberculosis was 55.8% (67/120) compared to 9.6% (16/167) amongst the control group (P < 0.0001: odds ratio = 11.50; 95% CI = 5.99-22.7). Common clinical presentations among children with TB were bronchopneumonia (45/162), miliary TB (30/162) and tuberculous lymphadenopathy (21/33). There were no significant differences in clinical presentation of TB between the HIV-negative and HIV-positive groups. The follow-up of those patients with tuberculosis was poor, with only 65 patients (55%) returning to the clinic for scheduled appointments after discharge. All the 16 patients who died did so within 60 days of discharge from hospital; all of them were seropositive for HIV. There were no deaths among the HIV-negative group. Despite the exclusion of thioacetazone from the treatment regimen, cutaneous reactions occurring within 8 weeks of commencing treatment were observed in 7 of the 65 (11%) patients, 2 of whom developed fatal Stevens-Johnson syndrome. All 7 patients were seropositive for HIV-1.

CONCLUSIONS

The seroprevalence rate of HIV type-1 among children with tuberculosis in Lusaka continues to rise; careful monitoring of anti-TB therapy (even in regimens excluding thioacetazone) for potentially lethal side effects should be carried out.

Necropsies in African children: consent dilemmas for parents and guardians

BACKGROUND

Necropsy examination provides a good index of the accuracy of clinical diagnosis and the quality of treatment, but its use in sub-Saharan Africa is limited.

AIMS

To identify the main reasons for parents'/guardians' refusal of consent for necropsy and to explore the issues affecting their decision.

METHODS

A sequential necropsy study of Zambian children between 2 months and 15 years dying of respiratory disease. When the parent/guardian refused permission for necropsy, the main reason given was recorded, after encouragement to express their specific concerns in their own words.

RESULTS

Parents/guardians of 891 of 1181 children (75.4%) refused to give permission, and 290 (24.6%) consented. Of those who refused, 43% did so on the grounds that it would be a "waste of time," as the diagnosis should have been made in life and the findings would now be of no benefit to them. More than one quarter of those who refused did so because a death certificate had already been issued and arrangements to transport the body had been made and could not be delayed. Traditional beliefs that ancestral spirits forbade the mutilation of dead bodies were cited by 77 (8.6%). Other reasons included the child not being their own or that they must seek permission from other family members who were not available (6%). Religious beliefs were not a major cause of refusal.

CONCLUSIONS

It is possible to achieve a rate of necropsy consent sufficient to undertake valuable clinical pathology studies on children in sub-Saharan Africa. The wide range of reasons cited for refusal points to the diverse and complex interaction of social and cultural factors affecting attitudes to necropsy examination. Medical staff need training and support to improve the uptake of clinical pathology services.

Minocycline-induced hepatitis with autoimmune features and neutropenia

Minocycline can cause various types of hepatotoxicity. We report an 18-year-old male who developed a delayed onset of minocycline-induced cholestatic hepatitis with autoimmune features and neutropenia. He responded to withdrawal of the drug and a short course of corticosteroids. If minocycline is to be administered, then periodic monitoring for hepatoxicity is recommended.

Epidemiological characteristics of human herpesvirus-8 infection in a large population of antenatal women in Zambia

Comprehensive data describing epidemiological characteristics of the human herpesvirus-8 or Kaposi's sarcoma-associated herpesvirus (HHV-8 or KSHV) infection among pregnant women in a central sub-Saharan Africa are not available. This study determined virus prevalence estimates and the risk factors associated with HHV-8 infection. Cross-sectional, enrollment visit data were analyzed from a prospective cohort study of perinatal transmission of HHV-8 in Lusaka, Zambia. Exposure data were obtained via structured interview, physical examination, medical chart review, and laboratory testing. Among 3,160 antenatal women serologically screened for HHV-8 between September 1998 and October 2000, 40.2% were seropositive. The HHV-8 positive women were more likely to be co-infected with HIV-1 than those who were HHV-8 negative (34% vs. 26%; P < 0.0001). Of 154 variables evaluated by logistic regression analyses, only three risk factors, have emerged as independent predictors of HHV-8 positive serology: diagnosis of genital warts, HIV-1 co-infection and primary education. The association of HHV-8 infection with genital warts and HIV-1 co-infection suggests heterosexual transmission of HHV-8. HIV-1 infection may also act as a marker for particular behaviors, which could be sexual in nature, that are associated with both HIV-1 and HHV-8 transmission. Since HHV-8 facilitates development of AIDS-related Kaposi's sarcoma (KS), the results of this study could be utilized to identify specific population groups of pregnant women who are at increased risk for this disease.

Study of the efficacy of toothpaste containing casein phosphopeptide in the prevention of dental caries: a randomized controlled trial in 12- to 15-year-old high caries risk children in Bangalore, India

Casein phosphopeptide (CPP) has the potential to be added to mouth rinses, gels, toothpastes, chewing gums and confectioneries. Until now CPP has been studied in vitro, in situ and in animals, but clinical trials are lacking. This study was conducted to evaluate the efficacy of CPP-containing toothpaste in preventing dental caries in schoolchildren. The study was conducted among 150 schoolchildren randomly divided into three groups, each using one of three types of toothpastes: (a) containing 2% w/w CPP; (b) containing 1,190 mg/kg fluoride as 0.76% sodium monofluorophosphate (SMFP); (c) placebo toothpaste without CPP or fluoride. Students brushed with the given toothpastes for 24 months. Oral hygiene and caries experience were assessed at baseline, 12 and 24 months. The increments in caries lesions were calculated and analyzed to assess the caries-preventive effect. A significant reduction in caries increment was observed among students using CPP toothpaste or SMFP toothpaste, compared with the group using the placebo toothpaste. The reduction in caries increment was not significantly different between the CPP and SMFP groups. Oral Hygiene Index score increased from the 12-month to the 24-month examination. It is concluded that CPP can be effectively incorporated into calcium carbonate-based toothpaste and that toothpaste containing CPP is effective in preventing caries. Toothpaste containing 2% CPP seemed to have an efficacy similar to paste containing 1,190 mg/kg SMFP in the prevention of caries.

Impact of the human immunodeficiency virus type-1 on common pediatric illnesses in Zambia

The seroprevalence of HIV-1 and in-patient mortality in children with common pediatric illnesses was studied. Between October 1990 and July 1991 at the Department of Paediatrics and Child Health, University Teaching Hospital (UTH), Lusaka, Zambia, mothers of all pediatric admissions were interviewed and counselled for enrollment of their children into the study. Of a total of 1323 children seen, 1266 children (600 female and 666 male) were enrolled into the study. Pneumonia (28 per cent), malaria (24 per cent), malnutrition (18 per cent), and diarrhoea (10 per cent) constituted over 80 per cent of the total admission diagnoses. Tuberculosis (5 per cent) was the fifth commonest cause of admission (61 out of 1266 children). A total of 354 out of the 1266 (28 per cent) children were found to be seropositive for HIV-1 compared to a seroprevalence rate of 9 per cent in children attending accident and emergency for traumatic injuries (P=0.001). High HIV-1 seroprevalence rates were found in children with tuberculosis (69 per cent), malnutrition (41 per cent), pneumonia (28 per cent). and diarrhoea (24 per cent). The overall mortality in hospital among HIV-seropositive children (19 per cent) was significantly higher than those who were HIV-seronegative (9 per cent) (P = < 0.0001).

Comparison of immuno-phenotypes of stem cells from human dental pulp and periodontal ligament

It has been established that human dental pulp and periodontal ligament contain a population of mesenchymal stem cells (MSCs). However, the phenotypic analysis in terms of putative stem cell markers expressed by these stem cell populations is incomplete. It is relevant to understand whether stem cells derived from closely related tissues are programmed differently. The aim of the present study is to analyze whether these stem cells depict distinct characteristics by gaining insight into differences in their immunophenotype. Dental pulp and periodontal ligament tissue samples were obtained from extracted impacted wisdom teeth. Cell cultures were analyzed for surface and intracellular markers by indirect immunoflourescence. Detailed immunophenotype analysis was carried out by flow cytometry using relevant markers. The present study data shows dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) expressed embryonic stem (ES) cell markers Oct-4, Nanog and mesodermal marker Vimentin by indirect immunoflourescence. PDLSCs, however, had a weak expression of Nanog. Immunophenotyping revealed strong expression of MSC markers (CD73, CD90) in DPSCs and PDLSCs. Differences were observed in expression of stemness-related markers. DPSCs displayed increased percentages of SSEA4, CD13 and CD166 and decreased CD9 expression compared to PDLSCs. Both stem cells express common MSC markers, different levels of expression suggests there might be more than one stem cell population existing within these tissues which differ in their embryonic status, and DPSCs are a more primitive stem cell population in comparison to PDLSCs.

Recent spatial aggregation tendency of rainfall extremes over India

Significant increase in the frequency of occurrences of rainfall extremes has been reported over several parts of the world. These extreme events were defined at individual grids without considering their spatial extent. Here, using ground-based observations over India during boreal summer, we show that the average size of spatially collocated rainfall extremes has been significantly increasing since 1980. However, the frequency of occurrences of such collocated extreme events remains unchanged. Around 90% of the total number of large-sized events (area ≥ 70 × 10³ km²) of our study period (1951 to 2015) have occurred after 1980. Some of the major floods in recent decades over India are attributed to these large events. These events have distinctive precursory planetary-scale conditions, unlike their smaller counterparts. As the underlying physical mechanisms of extremes rainfall events are size-dependent, their changing spatial extent needs to be considered to understand the observed trends correctly and obtain realistic future projections.

Evaluation of a patient with left ventricular assist device dysfunction

With the increasing number of LVAD recipients due to lack of donor availability and use of an LVAD as destination therapy, there will be a significant proportion of this population presenting with device related complications. Initial evaluation should be with TEE because conduit obstruction would be a significant complication, among others. As observed in this case report, it is sometimes difficult to noninvasively detect device malfunction, and even surgical exploration left questions unanswered. Echocardiography has been the principal modality used so far to assess the LVAD cannulas. More reliance on Doppler velocities and establishment of a normal range of values and flow profiles of the inflow and outflow cannulas are necessary. Baseline echocardiographic studies could be used for future comparisons. Fluoroscopy and selective angiography have also been reported to be helpful. We would also recommend measuring LV hemodynamics, which have not been previously described, as an additional mode of evaluation of this emerging problem. This case report demonstrates the need for additional noninvasive modalities for diagnosis of ventricular assist device malfunction.

Comparative Evaluation of Gingival Depigmentation using Tetrafluoroethane Cryosurgery and Gingival Abrasion Technique: Two Years Follow Up

OBJECTIVE

A comparative evaluation of the gingival depigmentation by using Tetrafluoroethane cryosurgery and the gingival abrasion technique - 2 years of follow up.

MATERIAL AND METHODS

Ten systemically healthy patients who were aged 18 to 36 years were selected for the study. Tetrafluoroethane was used for the cryosurgical depigmentation and the gingival abrasion technique used a coarse flame shaped bur. The presence or absence of pigmentation was tabulated, based on the GPI (Gingival Pigmentation Index). For the statistical analysis, Freidman's test was used.

RESULTS

The keratinization was completed within a week after the application of the cryogen and about 10 days after the gingival abrasion technique was done. The statistical analysis which was done after 90th, 180th days and 2 years. The p-value which was obtained (p<.001) showed the superiority of cryosurgery over the gingival abrasion. During the follow up period, no side effects were seen for both the techniques and the improved aesthetics was maintained upto 2 years.

CONCLUSION

The use of cryogen Tetrafluoroethane is easy, practical and inexpensive as compared to gingival abrasion, due to its high rate of recurrence. Hence, it is more acceptable to the patients and the operator. Further studies are needed to assess the long term effectiveness of the cryosurgical method of depigmentation.

Rotavirus gastro-enteritis in hospitalized children with acute diarrhoea in Zambia

The clinical and epidemiological aspects of rotavirus diarrhoea were studied in hospitalized children with acute diarrhoea in Lusaka, Zambia. Two hundred and fifty-six (24.0%) of 1069 children admitted to the study were shedding rotavirus. The rotavirus-positive rate was highest in children less than 1 year of age (37.0%) and it was also high in those less than 6 months old. Rotavirus diarrhoea was seen throughout the year with a higher rotavirus-positive rate in the dry season. In rotavirus-positive diarrhoea patients, more children were dehydrated (82.4%) than in the rotavirus-negative group (56.2%). Rotavirus infection was more common in the children with normal nutritional status (27.6%, 162/588) than in those with malnutrition (19.3%, 93/482). The associated case fatality rate in the rotavirus-positive group was 6.4%, significantly less than in the rotavirus-negative group (OR 0.44, 95% CI 0.24-0.79), and mortality cases were seen only in children less than 2 years old.