Study of myopathies by histological and histochemical methods with special reference to staining for desmin expression

An attempt was made to study the histological and histochemical changes as well as immunohistochemical changes in desmin expression occurring in four types of clinical myopathies e.g. Chronic ischaemic myopathy due to Buerger's disease (Group I), Carcinomatous myopathy (Group II), Metabolic myopathy (Group III) and Muscular dystrophy (Group IV). The number of cases studied were 16 cases, 15 cases, 4 cases and 5 cases respectively. The study revealed: (i) a combination of normal, degenerated, necrotic and regenerating fibres in different proportions in all the four groups having maximum number of degenerated fibres in Group I and Group IV, relatively more number of regenerating fibres in groups III and absence of necrotic fibres in Group I. (ii) Altered tinctorial property in most of the fibres indicating degenerated and regenerating fibres in all the groups with Masson's trichrome staining against inconstant staining with PTAH appear to be a good indicator for myopathy. (iii) The Desmin expression was week and irregular in most of the cases with most of the fibres probably due to reduction of desmin content probably indicating degenerated fibres, appear to be a good indicator for myopathy. (iv) Chronic ischaemic myopathy showed close resemblance with muscular dystrophy though no typical or distinct distinguishing feature could be identified in these four groups.

Cell mediated immune status in malignancy--pretherapy and post-therapy assessment

Twenty-eight cases of malignancies of different kinds were studied to assess T-cell activity and population before and after institution of therapy. Fifteen cases were diagnosed as non-metastasising squamous cell carcinoma of larynx, pharynx, laryngopharynx, hypopharynx and tonsils. Seven cases were non-metastasising infiltrating duct carcinoma of breast and 6 cases were non-Hodgkin's lymphoma (NHL). It was observed that 3 out of 15 cases (20%) of squamous cell carcinoma cases were Mantoux test (MT) negative with a T-cell population of less than 40%, 2 out of 7 cases (28.6%) of infiltrating duct carcinoma of breast were MT negative with a T-cell population of less than 40% and 3 out of 6 cases (50%) of NHL were MT negative with a T-cell population of less than 40%. The normal controls, consisting of apparently normal healthy adults, had a T-cell population of more than 40% and were all MT positive. The patients who showed a negative skin test and a T-cell population less than 40% were further subjected to assessment of T-cell population and activity after appropriate therapy, and clinical cure of the disease. It was observed that 2 out of 3 cases (66.66%) of squamous cell carcinomas, 2 out of 2 cases (100%) of adenocarcinomas and one out of 3 cases (33.33%) of NHL showed positive conversion with a T-cell population of more than 40%.

Dopamine D4 receptor-mediated inhibition of cyclic adenosine 3',5'-monophosphate production does not affect prolactin regulation

Under physiological conditions, PRL synthesis and secretion are predominantly under negative control by dopamine acting through dopamine D2 receptors present in the pituitary lactotroph cells. To investigate the role of D4 receptors in the regulation of PRL synthesis and secretion, we stably transfected the human D4 receptor complementary DNA into the somatomammotrophic cell line GH4C1. The pharmacological characteristics of D4 expressed in GH4C1 were in close agreement with previous D4 receptor studies in Chinese hamster ovary and COS-7 cells. In GH4C1 cells, activation of D4 receptor variants (D4.2, D4.4, and D4.7) resulted in a similar level of reduction in forskolin- and vasoactive intestinal peptide (VIP)-stimulated cAMP levels (33% and 50%, respectively). In addition, the forskolin-stimulated activity of cAMP response elements fused to the VIP promoter driving the lacZ reporter gene could be blocked by D4 activation. However, quinpirole treatment had a minimal effect on transiently expressed luciferase reporter gene driven by a proximal PRL promoter in one of the D4-expressing cell lines. In contrast, the dopamine D2short receptor expressing GH4ZR7 cells treated with quinpirole displayed a significant decrease (51.3 +/- 4.1%) in PRL promoter activity. VIP-stimulated PRL release was not affected by D4 receptor activation, whereas in GH4ZR7 cells, a significant decrease in VIP-stimulated PRL levels was observed. Neither PRL promoter activity nor PRL secretion levels were affected in control untransfected GH4C1 cells. From this study it appears that although the D4 receptor may be expressed in the anterior pituitary, it does not have a major effect on PRL promoter activity or PRL secretion in GH4C1 cells despite its ability to reduce cAMP production. This might explain why D4- over D2-preferring antipsychotics such as clozapine do not cause hyperprolactinemia.

Review the role of dopamine D4 receptors in schizophrenia and antipsychotic action

For the past 20 years the most enduring explanation for schizophrenia has been the dopamine hypothesis, which proposes that the dopaminergic system is overactive in this widespread disease. Classically, the D2 receptor formed the core of the dopamine hypothesis since there was considerable evidence for elevations of D2 receptor levels in the brains of schizophrenic patients, and because these receptors served as the primary target in mediating antipsychotic effects of most neuroleptics. However, the dopamine D4 receptor has recently received particular attention in this context. This is because the atypical antipsychotic, clozapine, which is effective in treating refractory schizophrenics without the side-effect profile of typical neuroleptics, displays a 10-fold higher affinity for D4 compared to D2 or D3 receptors. Furthermore, the concentration in plasma water of clinical doses ofclozapine correlates well with its in vitro binding affinity for D4, but not D2 or D3 receptors, suggesting that D4 is a potential target in mediating clozapine's antipsychotic effects. As well, marked elevations in the level of a D4-like site (not identical to the D4 receptor) has been seen in the striatum of postmortem schizophrenic brains, but not in control brains. Finally, the most interesting feature of the D4 receptor is perhaps the array of polymorphisms associated with it, creating structural diversity in this receptor that supercedes all other known catecholamine receptors. The existence of these D4 polymorphisms raises the possibility that structural variations of this receptor may be associated with an increased susceptibility to schizophrenia, or observed variations in individual response to clozapine treatment. However, several studies aimed at investigating these hypotheses could not establish a direct role of D4 in schizophrenia. Furthermore, no association was evident between the polymorphic forms of D4 and susceptibility to schizophrenia, or variable clozapine response. Nevertheless, investigations surrounding this receptor has been far from futile. The observations which support the idea that D4 might serve as a target for clozapine have significantly modified and extended our understanding of mechanisms underlying atypical antipsychotic treatment of schizophrenia, as well as the dopamine hypothesis for schizophrenia. Further characterization of this receptor may prove to be crucial in designing highly effective antipsychotic drugs with minimal contraindications.

Synaptic growth in the rod terminals of mice after partial photoreceptor cell loss: a three-dimensional ultrastructural study

Following partial loss of photoreceptor cells in the retina of mice afflicted by mutant genes, damaging light exposure, or old age, some of the remaining rod cells exhibited a process of growth in their synapses with the second order retinal neurons. This growth was recognized by the presence of multiple synaptic sites in some of the rod terminals in the outer plexiform layer. In this study, a comparative analysis of the microanatomical changes in the synaptic structures of the rod terminals in the retina of normal, rds homozygous and heterozygous mutant and light exposed albino mice was undertaken by using a computer-aided three-dimensional reconstruction. A rod terminal normally showed the presence of 1 synaptic complex consisting of a single synaptic ribbon located between 2 processes of horizontal cells and 2 bipolar cell dendrites. In a rod terminal showing an enlarged synaptic complex, 2 or 3 separate synaptic ribbons formed the centres of separate synaptic sites; each of the sites was characterized by the presence of 2 laterally placed horizontal cell processes and 2 bipolar cell dendrites. However, these processes from the multiple synaptic sites were observed to arise from the 2 horizontal and the 2 bipolar cell elements that were normally present in the rod terminal. Thus proliferation of synaptic sites in the rod terminals occurred through growth and sprouting from the processes of the second order neuronal components present within the terminals. The altered synaptic complexes in the variously affected groups were structurally comparable and appeared to have resulted from similar microanatomical changes. The increase in the frequency of rod terminals with multiple synaptic sites occurred as a sequel to increasing photoreceptor cell loss that was recorded at different age points in the different experimental groups. It is concluded that rod synapses in the adult mammalian retina possess structural plasticity that permits compensatory growth.

Cryptic initiation at the human D4 receptor reveals a functional role for the amino terminus

It was found that deletion of the initiator methionine of the D4 receptor results in the use of a cryptic initiation site in the putative first transmembrane region. We made use of this observation to investigate the role of the amino terminus of the D4 receptor. In vitro transcription and translation of D4.4 and a D4.4 deleted for the initiation codon (D4.4 delta NH2) resulted in the formation of protein products with a molecular mass of about 44 and 40.5 kDa, respectively. The molecular mass of 40.5 kDa suggests initiation in the putative first transmembrane region. Transient expression of various deletion mutants indicated that this receptor form can be expressed at up to 70% of the D4.4 control levels and provided support for the existence for an alternative translation initiation site in the first transmembrane domain, most likely at nucleotide +112 (the initiator methionine codon is designated as +1). The D4.4 delta NH2 mutant was stably expressed in CHO cells. Pharmacological analysis demonstrated no major differences in antagonist binding with the regular D4.4 receptor, while dopamine and quinpirole binding affinities were about 5-fold decreased. The half-maximal level (EC50) for blocking forskolin-stimulated cAMP levels by dopamine was about 10-fold lower as compared to D4.4. Furthermore, the functional efficacy is decreased by about 40%. These data suggest that the amino-terminal domain is not essential for proper expression, but does interfere with the functional activity of the receptor, possibly through stabilization of the active state. To our knowledge this is the first demonstration that the amino terminus of a dopamine receptor is involved in signal transduction.

Dopamine D4 receptor variant in Africans, D4valine194glycine, is insensitive to dopamine and clozapine: report of a homozygous individual

The D4Valine194Glycine receptor is a variant of the dopamine D4 receptor and is found in 12.5% of the Afro-Caribbean population. Glycine replaces valine at a position one amino acid away from a serine which is critical for the attachment of dopamine. To determine whether this mutation had an effect on the properties of the dopamine D4 receptor, we constructed this variant and tested the sensitivity of the expressed protein with various drugs. We found that the variant receptor was two orders of magnitude less sensitive to dopamine, clozapine and olanzapine. The variant receptor was insensitive to guanine nucleotide, indicating the absence of a high-affinity state or functional state. The one 15-year-old individual found homozygous for this variant also had sickle cell disease. The patient revealed an overall pattern of low weight and no axillary or pubic hair.

Fine needle aspiration cytology of ophthalmic lesions

Forty cases of ophthalmic lesions were subjected to fine needle aspiration cytology for pre-operative diagnosis which included retinoblastomas (5 cases), inflammatory and neoplastic lesions of the eyelid and lacrimal glands (29 cases) and extra-ocular orbital lesions (6 cases) inclusive of 3 cases of rhabdomyosarcomas. The lesions were distributed in both the eyes almost in equal proportions. Histological confirmation was obtained in 85% of cases; false positive in only one case with malignant neoplasm of the eyelid and false negative also in only one case with inflammatory pseudotumour which were, histologically, proved to be adenoma of tarsal gland and lymphocytic lymphoma respectively.

Modulation of intracellular cyclic AMP levels by different human dopamine D4 receptor variants

To investigate whether polymorphic forms of the human dopamine D4 receptor have different functional characteristics, we have stably expressed cDNAs of the D4.2, D4.4, and D4.7 isoforms in several cell lines. Chinese hamster ovary CHO-K1 cell lines expressing D4 receptor variants displayed pharmacological profiles that were in close agreement with previous data from transiently expressed D4 receptors in COS-7 cells. Dopamine stimulation of the D4 receptors resulted in a concentration-dependent inhibition of the forskolin-stimulated cyclic AMP (cAMP) levels. The potency of dopamine to inhibit cAMP formation was about twofold reduced for D4.7 (EC50 of approximately 37 nM) compared with the D4.2 and D4.4 variants (EC50 of approximately 16 nM). Antagonists block the dopamine-mediated inhibition of cAMP formation with a rank order of potency of emonapride > haloperidol = clozapine >> raclopride. There was no obvious correlation between the efficacy of inhibition of forskolin-stimulated cAMP levels and the D4 subtypes. Dopamine could completely reverse prostaglandin E2-stimulated cAMP levels for all three D4 receptor variants. Deletion of the repeat sequence does not affect functional activity of the receptor. The data presented indicate that the polymorphic repeat sequence causes only small changes in the ability of the D4 receptor to block cAMP production in CHO cells.

Fine needle aspiration cytology of bone and joint lesions: an assessment

Fine needle aspiration cytology and subsequent correlation with histology and therapeutic follow-up was done in 198 cases of bone and joint lesions. Overall accuracy was found to be 87.34%; false diagnosis was recorded in 4.5% of cases; 8.08% cases were excluded from correlation as they did not turn up for further treatment or follow-up after the diagnosis. False diagnosis was encountered mostly with inflammatory lesions and primary neoplasms, diagnosing osteosarcoma and Ewing's sarcoma as chronic inflammatory lesion, chondroma as chondrosarcoma and vice versa. The possible cause of default has been discussed. The benign cystic lesions could be diagnosed with almost 100% accuracy by fine needle aspiration cytology where 10% cases were excluded as they could not be followed up.

Study of benign superficial cysts by fine needle aspiration cytology

Fine needle aspiration cytology of 213 cases of different cystic lesions from various regions of body and different superficial organs was analysed in an attempt to present the experience of the authors in the diagnosis of such lesions. The predominant lesion diagnosed by fine needle aspiration cytology was adnexal cyst/sebaceous cyst (41 cases) followed by vascular hamartoma (40 cases) and thyroglossal cyst (9 cases). One hundred fifty-eight (74.2%) out 213 cases were confirmed histopathologically. There was false negative diagnosis in 14 cases (6.6%). The remaining 41 (19.2%) cases did not turn up for further treatment. The fallacies that have been recorded in the diagnosis of thyroid cysts, salivary gland cysts and breast cysts in respect of papillary cystic thyroid carcinoma, muco-epidermoid carcinoma of salivary gland and intraductal carcinoma with fibrocystic disease of breast respectively have been highlighted in the present study.

99Tcm-cystine, a renal function and imaging agent: a comparative study in dog with 131I-hippurate and 99Tcm-glucoheptonate to evaluate its functional and imaging characteristics

99Tcm-cystine, which has been proposed as a renal radiopharmaceutical for evaluating renal morphology and function in a single experiment, is compared with 131I-orthoiodohippurate (OIH) with respect to its renal clearance and extraction parameters and with 99Tcm-glucoheptonate (GHA) regarding its imaging characteristics. In spite of its comparable renal accumulation with 131I-OIH, its clearance (10.1 +/- 1.0 ml min-1 kg-1) was lower than that of 131I-OIH (21.5 +/- 0.9 ml min-1 kg-1) but was higher than that of 125I-iothalamate (5.4 +/- 0.6 ml min-1 kg-1). Extraction efficiencies of 99Tcm-cystine, 131I-OIH and 125I-iothalamate were 39 +/- 5, 64 +/- 4 and 27 +/- 3, respectively. The glomerular filtration components of 99Tcm-cystine and 131I-OIH were 26 and 16% of their respective clearances. In probenecid-treated animals the clearance of both agents was affected to a similar extent and fell to half of their respective control values, whereas tubular secretory components were found to be 19 and 31% of the controls. The kidney images obtained with 99Tcm-cystine were superior to those obtained with 99Tcm-GHA at different time points. Therefore, considering both renal function and imaging properties of 99Tcm-cystine it appears that this radiopharmaceutical offers some definite advantages over the currently available renal agents and commands further study.

Humoral immunity response in malignancies with special reference to the effect of radiotherapy

In view of the variability in the findings recorded by different authors in the level of immunoglobulins in patients suffering from malignancies, a study on 34 cases of six types of malignancies treated with radiotherapy (telecobalt and telecesium) was carried out to record the humoral response and also to compare the response during radiotherapy and after radiotherapy in these cases. Serum of 20 age-matched normal volunteers served as normal control. The study recorded that the pretherapy levels of IgA and IgG were raised in most of the cases; but the IgM was decreased than that of the control level. This is probably due to the fact that the selective clones of cells producing different types of immunoglobulins are responding to the malignancies in different ways. The midtherapy level of all immunoglobulins showed the value lower than the pretherapy level, but recovery was observed in the post-therapy period with all immunoglobulins in all the cases irrespective of the histological types of malignancies. It was also apparent from this study that the post-therapy gain in the level of immunoglobulins over midtherapy level was more pronounced in cases having telecobalt therapy. Assessment of humoral response in 25 patients suffering from squamous cell carcinoma of different grades revealed that the midtherapy fall and subsequent post-therapy gain had no definite correlation with grading.

Fallacies of the fine needle aspiration cytology of surgical lesions of liver

Seventy-six cases of surgical hepatomegaly were subjected to fine needle aspiration cytology (FNAC) for initial diagnosis. Primary malignancies, as suspected clinically with adjunction of other investigative procedures, were 29 cases of whom 25 were confirmed by biopsy or therapy. Secondary deposits in liver were 27 of whom 15 were confirmed by therapy. Inflammatory lesions were 9 of whom 6 were confirmed by therapeutic response with specific therapy. Benign lesions were 10 of whom 5 were confirmed by surgery. Diagnosis of malignancies of liver is rather easier than that of benign lesions like hydatid cysts of liver which were Casoni's test negative; and hepatocellular adenoma, as the aspirate in the former is clear fluid and that of the latter is only normal looking liver cells. Thus, in respect of benign lesions of liver, FNAC diagnosis may be clinched after due consideration to the clinical findings, radiological and ultrasonographic findings and ultimately confirmed by exploration. Thus the fallacy lies in aspiration of normal looking liver cells whereby the histology may prove it to be hepatocellular adenoma, well differentiated hepatocellular carcinoma and secondary deposits where the exact site has not been hit. Ultrasonogram (USG) guidance helps in these cases where the same facility is available. This fallacy can again be avoided, where USG guidance is not available, by imparting due importance to clinical findings, USG findings and also by repeat smear.