A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Visualisation of Kiss1 Neurone Distribution Using a Kiss1-CRE Transgenic Mouse

Kisspeptin neuropeptides are encoded by the Kiss1 gene and play a critical role in the regulation of the mammalian reproductive axis. Kiss1 neurones are found in two locations in the rodent hypothalamus: one in the arcuate nucleus (ARC) and another in the RP3V region, which includes the anteroventral periventricular nucleus (AVPV). Detailed mapping of the fibre distribution of Kiss1 neurones will help with our understanding of the action of these neurones in other regions of the brain. We have generated a transgenic mouse in which the Kiss1 coding region is disrupted by a CRE-GFP transgene so that expression of the CRE recombinase protein is driven from the Kiss1 promoter. As expected, mutant mice of both sexes are sterile with hypogonadotrophic hypogonadism and do not show the normal rise in luteinising hormone after gonadectomy. Mutant female mice do not develop mature Graafian follicles or form corpora lutea consistent with ovulatory failure. Mutant male mice have low blood testosterone levels and impaired spermatogenesis beyond the meiosis stage. Breeding Kiss-CRE heterozygous mice with CRE-activated tdTomato reporter mice allows fluorescence visualisation of Kiss1 neurones in brain slices. Approximately 80-90% of tdTomato positive neurones in the ARC were co-labelled with kisspeptin and expression of tdTomato in the AVPV region was sexually dimorphic, with higher expression in females than males. A small number of tdTomato-labelled neurones was also found in other locations, including the lateral septum, the anterodorsal preoptic nucleus, the amygdala, the dorsomedial and ventromedial hypothalamic nuclei, the periaquaductal grey, and the mammillary nucleus. Three dimensional visualisation of Kiss1 neurones and fibres by CLARITY processing of whole brains showed an increase in ARC expression during puberty and higher numbers of Kiss1 neurones in the caudal region of the ARC compared to the rostral region. ARC Kiss1 neurones sent fibre projections to several hypothalamic regions, including rostrally to the periventricular and pre-optic areas and to the lateral hypothalamus.

Positive margins in laparoscopic partial nephrectomy in 855 cases: a multi-institutional survey from the United States and Europe

PURPOSE

Open partial nephrectomy has emerged as the standard of care in the management of renal tumors smaller than 4 cm. While laparoscopic radical nephrectomy has been shown to be comparable to open radical nephrectomy with respect to long-term outcomes, important questions remain unanswered regarding the oncological efficacy of laparoscopic partial nephrectomy. We examined the practice patterns and pathological outcomes following laparoscopic partial nephrectomy.

MATERIALS AND METHODS

A survey was sent to academic medical centers in the United States and in Europe performing laparoscopic partial nephrectomy. The total number of laparoscopic partial nephrectomies, positive margins, indications for intraoperative frozen biopsy as well as tumor size and position were queried.

RESULTS

Surveys suitable for analysis were received from 17 centers with a total of 855 laparoscopic partial nephrectomy cases. Mean tumor size was 2.7 cm (+/-0.6). There were 21 cases with positive margins on final pathology, giving an overall positive margin rate of 2.4%. Intraoperative frozen sections were performed selectively at 10 centers based on clinical suspicion of positive margins on excised tumor. Random biopsies were routinely performed on the resection bed at 5 centers. Frozen sections were never performed at 2 centers. Of the 21 cases with positive margins 14 underwent immediate radical nephrectomy based on the frozen section and 7 were followed expectantly.

CONCLUSIONS

Early experience with laparoscopic partial nephrectomy in this multicenter study demonstrates oncological efficacy comparable to that of open partial nephrectomy with respect to the incidence of positive margins. The practice of intraoperative frozen sections varied among centers and is not definitive in guiding the optimal surgical treatment.

Acute ureteric calculus obstruction: unenhanced spiral CT versus HASTE MR urography and abdominal radiograph

The aim of this study is to compare the performance of unenhanced spiral CT to the combination of HASTE MR urography (MRU) and plain abdominal radiography (KUB) in patients suspected of having acute calculus ureteric obstruction. 64 patients with suspected acute calculus ureteric obstruction were evaluated. The presence of perirenal fluid, presence and level of ureteric obstruction and calculi were assessed on both techniques. 44 of 64 (69%) patients had acute calculus ureteric obstruction based on clinical, radiographic or surgical findings. MRU showed perirenal fluid in acute ureteric obstruction (77%) with a greater sensitivity than CT showed stranding (45%). The combination of fluid and ureteric dilation on MRU showed a sensitivity of 93% (CT 80%), specificity of 95% (CT 85%), and accuracy of 94% (CT 81%). There were 61 findings of either fluid or ureteric dilatation on MRU in 44 acutely obstructed kidneys compared with 37 similar findings on CT (p<0.005). Although there was excellent reproducibility (Kappa=/>0.75) in the finding of perirenal fluid on MRU, there was only fair interobserver agreement (Kappa<0.4) regarding perirenal stranding on CT. MRU/KUB showed ureteric calculi in 21/29 (72%) of patients with calculi seen by CT. Overall, MRU/KUB revealed 2.4 abnormalities per acutely obstructed ureter compared with 1.8 abnormalities detected by CT. MRU/KUB using HASTE sequences can diagnose the presence of acute calculus ureteric obstruction with similar accuracy to spiral CT. The technique has less observer variability and is more accurate than CT in detecting evidence of obstruction such as perirenal fluid.

T and B cell repertoire in gastric lymph follicles in children with Helicobacter pylori infection

Helicobacter pylori infection has been implicated in the development of gastrointestinal malignancy in adults and children. The histopathological processes that lead to such development are unknown. We compared the immune cell repertoire of mucosal lymph follicles in children with H. pylori infection to B cell type mucosal associated lymphoid tissue (MALT)-lymphoma of adults. The B and T cell populations residing within the lymph follicles and/or within B cell type MALT lymphoma were characteriZed by an immunohistochemical technique, utilizing B and T cell markers including: CD3, CD4, CD8 (T cells); CD20, CD40, GD74, BLA36, CD80, CD86 (B cells). Stain intensity was compared between the samples. T cell repertoire was observed within the lymph follicles, but not in the B cell MALT-lymphoma specimens. No significant difference was observed between the staining of CD40, CD74, CD8, and BLA36. The B cell markers, CD80 and CD86, were found within the centrocytic zone of the lymph follicle. In the B cell repertoire, no significant difference was observed between the lymph follicles of children with H. pylori infection and the adult MALT-lymphoma specimens except in CD20. B and T cells were in close anatomical proximity, enabling them to interact and exchange immunological information.

T and B cell repertoire in gastric lymph follicles in children with Helicobacter pylori infection

Helicobacter pylori infection has been implicated in the development of gastrointestinal malignancy in adults and children. The histopathological processes that lead to such development are unknown. We compared the immune cell repertoire of mucosal lymph follicles in children with H. pylori infection to B cell type mucosal associated lymphoid tissue (MALT)-lymphoma of adults. The B and T cell populations residing within the lymph follicles and/or within B cell type MALT lymphoma were characteriZed by an immunohistochemical technique, utilizing B and T cell markers including: CD3, CD4, CD8 (T cells); CD20, CD40, GD74, BLA36, CD80, CD86 (B cells). Stain intensity was compared between the samples. T cell repertoire was observed within the lymph follicles, but not in the B cell MALT-lymphoma specimens. No significant difference was observed between the staining of CD40, CD74, CD8, and BLA36. The B cell markers, CD80 and CD86, were found within the centrocytic zone of the lymph follicle. In the B cell repertoire, no significant difference was observed between the lymph follicles of children with H. pylori infection and the adult MALT-lymphoma specimens except in CD20. B and T cells were in close anatomical proximity, enabling them to interact and exchange immunological information.

Immunologic effects of gliotoxin in rats: mechanisms for prevention of autoimmune diabetes mellitus

Various fungal products, such as gliotoxin (GT), have immunomodulating activity, a fact exploited previously by our group for prevention of autoimmune diabetes mellitus in BB/Wor rats. To understand better the immunologic effects in GT-treated rats, splenocytes from 65-day-old prediabetic diabetes-prone rats were phenotypically characterized after chronic treatment with GT. A parallel study examined the direct effects of GT on splenocyte preparations incubated with the mycotoxin. In vitro treatment of splenocytes with GT revealed relative decreases in CD4+ and increases in CD8+ T-cell subsets, whereas in vivo treatment with GT did not result in detectable alterations in relative CD4+ and CD8+ cell subsets. We were unable to show significant effects on NK cells or MHC class II cells. However, in vitro and in vivo GT treatments significantly enhanced the detectable RT6 surface marker, a key regulatory element in autoimmune diabetes pathogenesis. This study showed that GT selectively affects certain lymphocyte subsets, possibly through the mechanism of apoptosis, which was increased in vivo as well as in vitro.

Effect of gliotoxin on development of diabetes mellitus in diabetes-prone BB/Wor rats

The object of this investigation was to determine if gliotoxin, an immunomodulating fungal secondary metabolite, is capable of preventing the development of autoimmune diabetes mellitus in diabetes-prone BB/Wor rats. Chronic treatment, consisting of 1 microg gliotoxin/g of body wt administered three times weekly from the age of 30 days through 120 days, reduced the incidence of diabetes from 90% diabetic by 120 days among vehicle-treated animals to 56% diabetic among gliotoxin-treated animals. This result was significant by life table analysis. Animals treated with gliotoxin maintained lower serum glucose levels even in the pre-diabetic state than control (vehicle-treated) rats. Gliotoxin at levels used in this study showed no appreciable effect on the viability of rat insulinoma (RIN 38) cells in culture and only slightly decreased their insulin secretion. Animals chronically treated with gliotoxin showed weight gains comparable to those seen in controls, and the effect of gliotoxin on peripheral blood leukocyte counts was not significant. The possibility that gliotoxin exerted its effect through immunomodulating effects was implied by the loss of white pulp in splenic follicles of gliotoxin-treated animals.

Laparoscopic nephrectomy for autotransplantation

Proximal ureteral injuries often require extensive reconstruction to repair. Management options include nephrectomy, ileal ureter interposition, extensive spiral bladder flaps, or autotransplantation. We report a patient who sustained a proximal ureteral avulsion and underwent a less invasive repair by way of a laparoscopic nephrectomy and subsequent autotransplantation.

Human vaginal mucosal immune system: characterization and function

OBJECTIVE

The mucosal immune system has been recognized as the first line of defense against foreign antigens. The limited information available on the mucosal immunity of the lower reproductive organs have restricted our ability to fight infections, especially, the sexually transmitted disease. The aim of this study was to characterize in-vitro the human vaginal lamina propria lymphocytes (VLPL), their cell surface phenotypes, and cellular function.

METHODS

VLPL were isolated from human vaginal mucosa by enzymatic techniques. Cell surface characteristics were investigated by immunohistochemistry and flow cytometric analysis. Cellular immune function was evaluated by 3H-thymidine incorporation studies and ornithine decarboxylase (ODC) activity.

RESULTS

Immunohistochemistry and flow cytometric analysis showed that the CD4/CD8 ratio of the human vaginal mucosa is reversed compared to the gut lamina propria lymphocytes (0.55 +/- 0.17). PHA and ConA mitogens enhanced VLPL thymidine incorporation, while PWM did not have any significant effect. Very high level of ODC activity was observed in VLPL after PHA stimulation.

CONCLUSIONS

The human VLPL can be isolated, characterized, and respond to a mitogenic stimulus. We postulate that further analysis of the vaginal immune system will enhance our understanding of local defence mechanisms which will help in the development of new therapeutic modalities against vaginal infections.

Effect of gliotoxin on human polymorphonuclear neutrophils

OBJECTIVES

Candida albicans is known to produce gliotoxin, which has several prominent biological effects, including immunosuppression. Interference with host defenses may arise from the effects of this toxin on leukocyte structure and function.

METHODS

Flow cytometric analysis revealed that polymorphonuclear leukocytes (PMN) were more sensitive to gliotoxin than were mononuclear cells. Structural and various functional aspects of PMN exposed to gliotoxin were studied.

RESULTS

Gliotoxin at (1 microgram/mL) did not affect the viability but did diminish PMN chemotaxis and reduced their ability to ingest particles. Other functional aberrations included decreased nitroblue tetrazolium dye reduction, decreased superoxide production, and release of lactoferrin suggesting by degranulation. Gliotoxin also affected the ability of PMN to kill Escherichia coli.

CONCLUSIONS

This study suggests a previously unrecognized potential virulence factor of C. albicans that could contribute to persistence of yeast colonization or recurrence of symptomatic infection through diminished host resistance.

Effect of gliotoxin on human polymorphonuclear neutrophils

OBJECTIVES

Candida albicans is known to produce gliotoxin, which has several prominent biological effects, including immunosuppression. Interference with host defenses may arise from the effects of this toxin on leukocyte structure and function.

METHODS

Flow cytometric analysis revealed that polymorphonuclear leukocytes (PMN) were more sensitive to gliotoxin than were mononuclear cells. Structural and various functional aspects of PMN exposed to gliotoxin were studied.

RESULTS

Gliotoxin at (1 microgram/mL) did not affect the viability but did diminish PMN chemotaxis and reduced their ability to ingest particles. Other functional aberrations included decreased nitroblue tetrazolium dye reduction, decreased superoxide production, and release of lactoferrin suggesting by degranulation. Gliotoxin also affected the ability of PMN to kill Escherichia coli.

CONCLUSIONS

This study suggests a previously unrecognized potential virulence factor of C. albicans that could contribute to persistence of yeast colonization or recurrence of symptomatic infection through diminished host resistance.

Appendicitis complicating pregnancy

Abdominal pain is a common symptom in pregnancy. Its etiology is diverse and diagnosis often poses a problem. Inflammatory disorders of extra-uterine origin such as appendicitis should always be considered as a possible cause. Three cases of appendicitis complicating pregnancy managed at the Queen Elizabeth Hospital, Barbados during the year 1993 are documented. Two presented in the antenatal period and the third postpartum. The clinical manifestations and the difficulties encountered in diagnosis are emphasised.

Crystallization and preliminary X-ray analysis of phosphoporin from the outer membrane of Escherichia coli

Phosphoporin is a pore-forming transmembrane protein that spans the outer membrane of Escherichia coli and facilitates the diffusion of phosphates and phosphorylated compounds. Phosphoporin has been crystallized in several different crystal forms, although only one appears to be suitable for X-ray analysis. These crystals, which are hexagonal plates, diffract X-rays to 3 A resolution and belong to the space-group P6(3)22, with unit cell dimensions a = b = 121 A and c = 111 A.

Nicotinic pharmacology of anatoxin analogs. II. Side chain structure-activity relationships at neuronal nicotinic ligand binding sites

Eighteen analogs of (+)-anatoxin-a were evaluated for nicotinic potency at two putative nicotinic acetylcholine receptor sites in the central nervous system. The affinities of the analogs for [3H]nicotine and [125I]alpha-bungarotoxin binding sites were compared. This series of analogs, with modifications to the side chain moieties of the parent structure, enables the importance (for nicotinic binding) of hydrogen bonding strength, planarity, size and steric configuration of this region of the molecule to be assessed. These studies confirm the importance of the side chain stereochemistry and the subordinate role of H-bonding strength of anatoxin analogs. Of all the analogs tested, the parent compound (+)-anatoxin-a is the most potent competitor of ligand binding. Although all analogs have higher affinity at the [3H](-)-nicotine site compared to the alpha-[125I]bungarotoxin site, the rank order of potency is generally the same at both central nervous system sites, and agrees with the order at the muscle nicotinic receptor. However, the simple methoxyamide and the isoxazolidide analogs appear more selective for the neuronal nicotinic receptor subtype identified by [3H](-)-nicotine, indicative of structural differences among the agonist recognition sites.

Results of surgical treatment of neonatal necrotizing enterocolitis

In 6 years, 74 neonates were treated for necrotizing enterocolitis, 40 (54 per cent) of whom underwent operation. The early postoperative mortality rate was 23 per cent and there was one late death. Of the 30 postoperative survivors, two have short bowel syndrome, two have chronic respiratory disease, two are partially sighted, and five (17 per cent) have severe developmental delay. Only 15 (50 per cent) survivors enjoy good health.

A lesson in intestinal atresias

A girl with an atresia of the distal ileum and another in the sigmoid colon is reported, as are the inadequacies in her management. The association of an ileal atresia with a separate colonic atresia does not seem to have been previously reported.