The role of smooth-ended ameloblasts in enamel protein degradation in the rat incisor pigmentation

Rats were perfused with glutaraldehyde. The lower incisors were dissected free. Mid-sagittal slice was cut through the entire incisor, demineralized. The pigmentation zone was isolated and further sliced into cross sections. These sections were incubated for CMPase. CMPase reaction product were associated with the lateral cell membrane of subclass II and Subclass III. This localization confirm the role of extracellular space of SAs as a route of enamel proteins during maturation.

A comparative study of picomolar affinity 2-[(125)I]iodomelatonin binding sites in the hearts of three salmonid species

The hearts of three cultured salmonid species, collected at either mid-light or mid-dark were studied for their binding to 2-[(125)I]iodomelatonin, a specific melatonin agonist. The binding was saturable, reversible, and highly specific. The equilibrium dissociation constant (Kd) ranged from 30.1 ± 3.0 pmole 1(-1) in Arctic charr (Salvelinus alpinus) to 40.5 ± 2.3 pmole 1(-1) in rainbow trout (Oncorhynchus mykiss) indicating a high binding affinity. The maximum density of binding (Bmax) was at the low femtomolar level of 0.57 to 0.87 fmole mg(-1) protein. Higher Bmax appeared to be demonstrated in the mid-light samples when compared to the mid-dark samples but the difference was not significant (p > 0.05). Competition study with various indoles showed the following order of potency: 2-iodomelatonin > melatonin > 6-chloromelatonin ≫ N-acetylserotonin ⋙ serotonin. Guanosine 5'-O-(3-thiotriphosphate) (GTPγS) strongly inhibited the binding (IC50 = 0.66 μmole 1(-1)) in the rainbow trout heart, suggesting that these binding sites belong to the superfamily of G-protein linked receptors. Our results suggest the presence of melatonin receptors in the fish heart. In addition, there was no marked intraspecies differences in Kd, Bmax and specificity that could be correlated with the phylogeny or life history of the salmonid species.

Melatonin activity rhythms in eyes and cerebral ganglia of Aplysia californica

In this study, we used a sensitive and specific radioimmunoassay to detect a substance which appears to be melatonin, an acetylation and methylation product of serotonin, in the eyes and central nervous system of the opisthobranch mollusc Aplysia californica. This identification was confirmed in the eyes by HPLC with fluorimetric detection. Melatonin activity was high in the eyes during the day and in the cerebral ganglia during the night. Only small amounts of melatonin were present at midday or midnight in the pedal ganglia. A single 1-hr exposure to light in the middle of the dark phase resulted in a sharp increase of melatonin in the eyes, whereas no such activity was detectable in cerebral and pedal ganglia. Eyes maintained in culture exhibited a diurnal rhythm of released melatonin activity over a 3-day period. These results suggest that melatonin is produced in A. californica in a rhythmic pattern different from that associated with pineal melatonin production in vertebrates.

Rhythmic secretion of melatonin by the superfused pike pineal organ: thermo- and photoperiod interaction

In the pineal organ of the pike (Esox lucius, teleost), the rhythmic production of melatonin by the photoreceptor cells is governed by a population of endogenous circadian oscillators, synchronized and entrained by the light/dark (L/D) cycle. Production of melatonin is inhibited by light and highly increased in the dark. In the present study, isolated and superfused pike pineals were exposed to a 24-hour temperature cycle of high (10 degrees C) or low (4 degrees C) amplitude, either under L/D, or under constant darkness. Under L/D, photoperiod is the dominant entraining stimulus for the melatonin secretion rhythm. It was high during the dark phase and low during the light phase, either under cold light/warm dark or under warm light/cold dark conditions. Under a warm light/cold dark cycle, the amplitude of the melatonin rhythm was reduced. In pineals cultured at 10 degrees C, a 20 degrees C temperature pulse potentiated or reduced the night-induced rise in melatonin production when applied, during the dark or during the preceding light phase, respectively. Under constant darkness, high- or low-amplitude temperature cycles could synchronize the rhythmic production of melatonin, which peaked with the high temperature. However, the shape of the oscillation could appear modified under warm subjective-L/cold subjective-D, depending on the experimental conditions. Finally, the rhythmic release of melatonin synchronized by a temperature cycle under constant darkness was no longer observed after removal of the external zeitgeber. The present study provides direct evidence that the pineal acts as a photothermotransducer.

Fine-needle aspiration biopsy diagnosis of extrarenal malignant rhabdoid tumor

Two cases of extrarenal malignant rhabdoid tumors are presented in which diagnosis was suggested by fine-needle aspiration biopsy and confirmed by histologic and electron microscopic examination. Fine-needle aspiration smears in both cases revealed round to polygonal cells with vesicular nuclei and prominent nucleoli. Several tumor cells contained cytoplasmic inclusions composed of intermediate filaments. A majority of the tumor cells stained strongly for vimentin and cytokeratin. Electron microscopic examination revealed many cells with large aggregates of intermediate filaments corresponding to the cytoplasmic inclusions. Fine-needle aspiration biopsy may be used for diagnosing malignant rhabdoid tumor. The diagnosis may be further confirmed by immunohistochemistry and electron microscopy.

Effect of gibberellic acid on broiler chickens performance and some metabolic parameters

Feeding 2-weeks old broiler chicks on gibberellic acid (GA3)-containing diets (0, 1, 5, 25 and 125 ppm) for 3-weeks led, generally, to nonsignificant increase of body weight, decreased feed consumption and better feed conversion (on 25-125 ppm). Yet, the percentages of the carcass and the other organs (liver, gizzard, heart) and glands (adrenal, thyroid and pituitary) weights were lower comparing with the control (0 level). Blood protein and magnesium concentrations raised significantly. Blood glucose increased but not significantly. There was remarkable decrease (P < or = 0.01) in transaminases activity. The muscular protein decreased, whereas the fat percentage significantly increased. The bone reflected lower density and mineral (calcium, magnesium and phosphorus) contents. GA3 led to numerous histological lesions in different organs. Two-weeks withdrawal period did not ameliorate the negative effects of GA3-inclusion whether on the dressing percentages, blood picture, or on the muscles and bone constituents.

Kikuchi disease and its association with systemic lupus erythematosus

Histiocytic necrotizing lymphadenitis or Kikuchi disease is a rare entity; furthermore, its association with systemic lupus erythematosus (SLE) was only described in 11 patients in seven reports in the world literature. As the disease affects young women and manifests as a systemic illness associated with lymphadenopathy (usually cervical), the importance of continued follow-up to see whether it remains a self-limiting process or evolves into systemic lupus erythematosus should be emphasized. We present the clinical and histopathological data of eight patients with Kikuchi disease diagnosed in one tertiary care centre, two of whom evolved into SLE. White blood count was normal in all except the two patients who evolved into SLE; erythrocyte sedimentation rate was elevated in all patients tested. Kikuchi disease could be misdiagnosed as non-Hodgkin's lymphoma or tuberculous lymphadenitis; furthermore, awareness of its association with SLE is emphasized.

2-[125I]iodomelatonin binding in the brains of four salmonids

[125I]-Labelled iodomelatonin binding to brain membrane preparations was examined in adults of 4 species of salmonid fishes; 3 species were of cultured stock (Arctic charr, Atlantic salmon, rainbow trout) and 1 was taken from the wild (coho salmon). The specific binding of 2-[125I]iodomelatonin to the brain membrane preparations collected from all 4 species was specific, stable, saturable, reversible and of high affinity. Competitive inhibition studies showed that only melatonin, 2-iodomelatonin, 6-chloromelatonin and N-acetylserotonin showed significant inhibition of radioligand binding. In the 4 species studied, the equilibrium dissociation constant (Kd) ranged from 9.3 +/- 0.2 pmol/l in coho salmon to 13.2 +/- 0.7 pmol/l in rainbow trout, and those in rainbow trout were significantly higher (p < 0.05) than in the others. The maximum number of binding sites (Bmax) of the Atlantic salmon preparations (14.3 +/- 0.7 fmol/mg protein) was significantly higher than those of the other 3 species (means ranging from 9.9 to 11.6 fmol/mg protein). Hill coefficients of all 4 species were close to unity indicating one class of binding site. The interspecies differences in Kd and Bmax could not be correlated with phylogeny or life history of the various species. For the three cultured species, samples were collected at both mid-dark and mid-light to examine for diurnal variations; none were found.

Laparoscopic cholecystectomy: analysis of the complications at a community hospital

With the worldwide acceptance of laparoscopic cholecystectomy (LC) as the treatment of choice for symptomatic gallbladder disease, great concern has grown over the spectrum of complications associated with this new procedure. The nature, causes, frequency, as well as ways to avoid these complications have been the subject of many articles and studies. Although it is established that the frequency of the major complications decreases with increased experience, there will still be new surgeons performing the procedure with limited experience in the early stages of their surgical practice. Therefore, continuous efforts should be exerted to bring to a minimum the number of serious morbidities, especially common bile duct injuries. Review of each institution's experience and sharing it with other medical centers may be a valuable approach to achieve this important goal. In this report, we will analyze the spectrum of complications we encountered during our experience with LC as well as some recommendations to avoid some of the serious morbidities related to this procedure.

Small round cell tumor with divergent differentiation: cytologic, histologic, and ultrastructural findings

A case study of desmoplastic small round cell tumor with divergent differentiation in a 13-yr-old boy is presented. Clinical, cytologic, histologic, immunohistochemical, and ultrastructural findings are reported. There was a close correlation between the various histologic and cytologic patterns. Immunohistochemical studies revealed strong positivity of many of the tumor cells for cytokeratin, vimentin, and desmin. Ultrastructurally, some of the tumor cells contained aggregates of cytoplasmic intermediate filaments. Fine-needle aspiration biopsy may suggest the diagnosis of desmoplastic small round cell tumor. Confirmation of the diagnosis may be provided by immunohistochemistry and electromicroscopy.

Effect of multiple light scattering and self-absorption on the fluorescence and excitation spectra of dyes in random media

The absorption, fluorescence, and excitation spectra of a dye in a highly scattering random medium were studied experimentally. The intrinsic absorption spectrum of the dye does not change in the presence of scatterers, but the presence of scatterers in the media will change the observed fluorescence spectra. The observation is accounted for by the change in the photon trajectory path length for the fluorescence emission.

Apparent absence of BCL-2 rearrangement in ten Saudi follicular lymphomas: A preliminary report

Specific chromosomal translocations are often found to be associated with distinct types of human neoplasms. The t(14;18) is considered to be a cytogenetic hallmark of the follicular lymphomas found mostly in American patients. This chromosomal translocation occurs through a 3' untranslated region (either major breakpoint region [mbr] or minor cluster region [mcr]) of the bcl-2 proto-oncogene in chromosome 18 and the JH region of the immunoglobulin (Ig) gene in chromosome 14. In the present study, the polymerase chain reaction (PCR) was used to detect a fusion DNA fragment generated from bcl-2/JH rearrangement either through mbr or mcr in 10 follicular lymphomas in Saudi Arab patients. Surprisingly, none of these cases showed any evidence of bcl-2 gene rearrangement through mbr or mcr. The absence of usual bcl-2/JH recombination in Saudi follicular lymphomas is intriguing and may suggest that the occurrence and mode of bcl-2 gene rearrangement in this lymphoma varies in different patient populations.

Multiple circadian oscillators in the photosensitive pike pineal gland: a study using organ and cell culture

The fish pineal organ contains typical and, in some species, modified photoreceptor cells involved in the photoperiodic control of melatonin production. In the majority of species studied, the rhythm in melatonin production is driven by an intra-pineal circadian oscillator synchronized by the light:dark cycle. In the present study, it is shown that the endogenous rhythm in melatonin release of superfused pike pineals maintained under constant darkness is expressed at temperatures of 19 degrees C, 20 degrees C, 25 degrees C, and 30 degrees C (period > 24 hr), but not at temperatures of 10 degrees C and 15 degrees C. Under constant darkness, pineal fractions containing either typical photoreceptors, modified photoreceptors, or both behaved like total organs. Dissociated pike pineal cells, cultured statically at 20 degrees C, expressed a high amplitude rhythm in melatonin secretion under a light:dark cycle. Under constant darkness, circadian oscillations, which appeared better sustained than in organ culture, were also observed. This study provides the first evidence that the rhythmic production of melatonin, by a fish pineal, is driven by a population of circadian oscillators or clocks. It is hypothesized that each typical and modified photoreceptor might be the locus of a circadian clock. Damping of the overall rhythm under constant darkness might reflect the desynchronization (uncoupling) between these clocks and/or damping of individual oscillators.

Myelodysplastic syndrome with prolonged reticulocyte survival mimicking hemolytic disease

A patient with myelodysplastic syndrome (refractory anemia) with marked and persistent reticulocytosis is presented. A referring diagnosis of hemolytic disease had been made. However, the 51Cr red cell survival was normal (T1/2 24 days). Reticulocyte morphology, red cell creatine content, and in vitro reticulocyte survival studies have suggested that the reticulocytosis arose as a consequence of delayed maturation of the reticulocytes. Two patients with myelodysplastic syndrome and delayed reticulocyte maturation have previously been described; in both patients, however, red cell survival was also shortened. Anemia with reticulocytosis, mimicking hemolytic disease, may be an unusual presentation of myelodysplastic syndrome.

Histologically advanced chronic hepatitis C treated with recombinant alpha-interferon: a randomized placebo-controlled double-blind cross-over study

Chronic hepatitis C is common in Saudi Arabia and most often presents in an advanced stage. To assess the response of patients to interferon, a randomized placebo-controlled double-blind study was undertaken. All but 1 patient had cirrhosis or fibrosis before interferon. After a 24-week observation period patients received alpha 2a interferon, 3 mega units sc tiw or placebo for 24 weeks, then the opposite treatment for another 24 weeks followed by 24 weeks of observation. Liver biopsies were performed before and after each of the treatment phases. Twenty-two out of 24 patients completed the study. The mean alanine aminotransferase (ALT) levels fell from 150.7 +/- 118.7 units/l to 91.0 +/- 42.6 units/l after 6 months interferon treatment (P = 0.03) but only 3 patients (14%) had complete normalization of mean ALT levels and 4 (18%) had > 50% reduction. The mean hepatitis activity index fell from 12.2 +/- 2.6 immediately before to 11.6 +/- 2.5 just after interferon (P = 0.4). After interferon there was an insignificant raise in 6-month mean ALT. Hepatitis C virus-RNA was positive in all 17 patients tested and remained so after treatment. Side-effects were mild and well tolerated. Alpha interferon 3 mega units tiw for 24 weeks is not an effective treatment of histologically advanced chronic hepatitis C.

Fine-needle aspiration biopsy of Langerhans histiocytosis (histiocytosis-X)

A series of 14 fine-needle aspiration biopsies (FNAB) from histologically proven cases of histiocytosis-x (Hx) were reviewed. The smears revealed a variable mixture of Langerhans cells, eosinophils, macrophages, polymorphonuclear cells, and giant cells. Based on the predominant cells present, the cases were further categorized as Langerhans cell predominant (nine cases), eosinophil predominant (two cases), and macrophage predominant (three cases). Langerhans cells were usually polygonal without significant evidence of phagocytosis and frequently contained indented nuclei. In three cases, several Langerhans cells showed prominent dendritic processes. Electron microscopy in 10 cases revealed Langerhans cells with varying degrees of morphologic differentiation. All cases studied revealed Birbeck granules. These findings indicate that FNAB may be an effective technique for diagnosing Hx.

Light and electron microscopic observations on rat molar periodontal ligament after intraperitoneal injection of vinblastine

The effect of intraperitoneal injection of Vinblastine sulfate on rat periodontal ligament was studied. Cells still synthetize collagen after 2 hours of the injection with evidence of loss of extracellular collagen fibers orientation. Tubular lysosome could not be detected after 2 hours with formation of lysosomal clusters in the cell center. After 4 hours of administration, evidences of cell degeneration were observed. The present study has shown that Vinblastine produces effect on fibroblasts as early as two hours after injection.

Lysosomal system of von Ebner's salivary gland in the rat

We have examined the morphology and distribution of lysosomes in von Ebner's salivary gland utilizing TMPase as a marker. TMPase reactivity was detected basally, laterally and in the center of the cells. They include AV, Rb, MVBs and dense bodies. TL were detected for the first time in between the secretory granules and in the lateral parts of exocrine acinar cells. They were parallel to RER. In addition direct continuity between TL and MVBs and dense bodies was observed. The new locations and relations of TL supports their role in pinocytotic processes and cellular regularity processes.

Chronic non-A, non-B hepatitis complicated by end-stage renal failure treated with recombinant interferon alpha

Chronic non-A, non-B hepatitis occurs in 50% of Saudi patients with end-stage renal failure and requires long-term hemodialysis since it is a contraindication to renal transplantation. Thirteen patients with biochemical and histological documented chronic non-A, non-B hepatitis (11 with HCV antibodies) entered a double-blind placebo controlled cross-over study, in which Roferon A 3 MU or placebo were administered subcutaneously 3 times weekly after hemodialysis for 6 months. The mean ALT fell significantly from pretreatment levels of 74.7 (95% confidence interval (CI) 54.7, 92.5) (13 patients in the 6-month run-in period) and 66.8 (CI 47.7, 85.8) (7 patients in the run-in period + 6 patients in the placebo period) (difference NS) to 37.6 (CI 21.0, 54.2) during interferon treatment (P < 0.005). In 10/13 patients (77%) ALT levels became normal. In the 6-month follow-up period immediately after therapy, the mean ALT was 45.2 (CI 28.0, 62.0). Although this change was not significant (P = 0.49), only 7 of these 10 patients sustained biochemical remission in the 6-month follow-up period. The corresponding total Histological Activity Index improved from 8.9 (CI 7.5, 10.3), 8.9 (CI 7.2, 10.7) (difference NS) to 6.2 (CI 3.9, 8.5) (P < 0.05; P = 0.052, respectively). Intralobular inflammation and periportal inflammation showed the most significant changes. Five of 13 (39%) and 2/13 patients (15%) had complete resolution of piecemeal necrosis and intralobular inflammation, respectively. Toxic effects of interferon were mild, early and self-limiting.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary hepatic vipoma

A 35-yr-old male presented with a 3-yr history of voluminous watery diarrhea. He had episodes of severe generalized weakness which responded to fluid and electrolyte replacement therapy. Investigations revealed a solitary liver mass and an elevated vasoactive intestinal polypeptide level. An extensive work-up did not show any other extrahepatic primary lesion. Surgical resection ameliorated all of his symptoms, accompanied by a decrease in the vasoactive intestinal polypeptide level. We believe that this patient represents a case of primary hepatic vipoma syndrome. To our present knowledge, this has not been reported previously. We discuss the clinical manifestations, investigations, and management of the case.

Effects of mesencephalic lesion on testes, seminal vesicles and adrenal glands of albino rats

The role of mesencephalic reticular formation on testicular structure, seminal vesicles, adrenal glands and kidneys of albino rats was investigated. Mesencephalic reticular formation lesions were produced using two epoxy-coated stainless steel electrodes. Electrolytic lesions resulted in atrophy of the testes, seminal vesicles and adrenal glands. The degree of atrophy was statistically significant in these organs (P < 0.01). However, there were no significant changes in the kidneys of lesioned animals. This study strongly suggests that the mesencephalic reticular formation influences the histomorphology of testes, seminal vesicles and adrenal glands.

Giant cell tumour of bone. A surgical approach to grade III tumours

Thirty-one patients with giant cell tumours of bone (BGCT) were treated at our hospital by a conservative approach between 1975 and 1988. 94% of the tumours were grade III (Campanacci) and the follow up was from 2 to 13 years. In the 20 patients who had a modified intralesional excision (curettage) with bone grafting and cement, 5 recurrences occurred. There was one soft tissue recurrence in the 11 patients who had marginal or wide excisions. All recurrences were in grade III lesions. We conclude that grade III BGCT can be treated by modified intralesional excision provided the articular surfaces and part of the metaphysis are intact.