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Biomedical subjects

J Nicholls

Publications and source records attributed to J Nicholls.

At least 19 recordsLinked to original sources
PubMed1997

Residual mass following chemotherapy of seminoma.

BACKGROUND: The residual mass so frequently found after chemotherapy of advanced seminoma may consist entirely of benign tissue or may contain residual disease amenable to adjuvant therapy. PATIENTS AND METHODS: A detailed retrospective analysis was performed on 45 patients treated with cisplatin based chemotherapy for advanced seminoma between 1978 and 1994. RESULTS: The probability of a residual mass after chemotherapy was higher if the pre-treatment mass diameter was > 5 cm (78% versus 15%, P = 0.0009). Of 33 patients with residual masses following cisplatin chemotherapy, 4 were explored surgically showing fibrosis only, 15 were treated by adjuvant radiotherapy and 14 were managed by observation alone. Recurrence occurred in 2 of 14 patients managed by observation and in 2 of 15 managed by radiotherapy. There was no evidence that risk of recurrence was related to diameter of residual mass. CONCLUSION: Residual masses persisted following cisplatin based combination chemotherapy for seminoma in 73% of cases. In our study, recurrence was rare and there was no evidence that this was influenced by either the size of the residual mass or the use of adjuvant therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Fertility after chemotherapy for testicular germ cell cancers.

PURPOSE: To analyze the probability of recovery of spermatogenesis after orchidectomy and cisplatin-based chemotherapy (CT) for testicular germ cell cancer. PATIENTS AND METHODS: One hundred seventy-eight patients treated between 1979 and 1991 were selected by the requirement of sperm count both pre-CT and post-CT. Counts were classified as normospermic (NS) if more than 10 x 10(6)/mL, oligospermic (OS) if 1 to 9 x 10(6)/mL, and azoospermic (AS) if less than 1 x 10(6)/mL. The median follow-up time after CT before sperm analysis was 30 months. RESULTS: Analysis of 170 patients whose spermatogenesis was reassessed at least 1 year after CT showed that of 89 patients whose pre-CT counts were NS, the post-CT count was NS in 64%, OS in 16%, and AS in 20%. There was clear evidence for continued recovery beyond 1 year; the probability of spermatogenesis increased to 48% by 2 years and 80% by 5 years. There was a significantly higher probability of recovery to OS and NS count levels in the 54 patients treated with carboplatin-rather than cisplatin-based therapy. There was an independent and similar effect of normal pre-CT count. There was a reduced probability to recover to OS in the 26 patients treated with more than four cycles of CT. A prognostic model identified three groups with 25%, 45%, and 82% probabilities of recovering spermatogenesis by 2 years after CT. CONCLUSION: Analysis of pre-CT sperm count together with details of planned treatment can be used to predict recovery of spermatogenesis following germ cell CT.

Adolescent↗
PubMed1996

Extensive alternative splicing within the amino-propeptide coding domain of alpha2(XI) procollagen mRNAs. Expression of transcripts encoding truncated pro-alpha chains.

Heterogeneity in type XI procollagen structure is extensive because all three alpha(XI) collagen genes undergo complex alternative splicing within the amino-propeptide coding domain. Exon 7 of the human and exons 6-8 of the mouse alpha2(XI) collagen genes, encoding part of the amino-propeptide variable region, have recently been shown to be alternatively spliced. We show that exon 6-containing mRNAs for human alpha2(XI) procollagen are expressed at 28 weeks in fetal tendon and cartilage but not at 38-44 days or 11 weeks. In the mouse, exon 6 is expressed in chondrocytes from 13.5 days onward. We recently identified conserved sequences within intron 6 of the human and mouse alpha2(XI) collagen genes, containing additional consensus splice acceptor and donor sites that potentially increase the size of exon 7, dividing it into three parts, designated 7A, 7B, and 7C. We show by reverse transcription polymerase chain reaction and in situ hybridization that these potential splice sites are used to yield additional alpha2(XI) procollagen mRNA splice variants that are expressed in fetal tissues. In human, expression of exon 7B-containing transcripts may be developmental stage-specific. Interestingly, inclusion of exon 7A or exon 7B in human and mouse alpha2(XI) procollagen mRNAs, respectively, would result in the insertion of an in-frame termination codon, suggesting that some of the additional splice variants encode a truncated pro-alpha2(XI) chain.

Alternative Splicing↗
PubMed1996

Unusual endocrine presentations of nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma is endemic in Southern China and the majority of patients present with local symptoms due to the tumor. METHODS: This report describes two unusual cases of occult nasopharyngeal carcinoma in which the patients initially presented with endocrine manifestations. RESULTS: The first patient presented with Cushing's syndrome secondary to ectopic adrenocorticotropic hormone (ACTH) production. Nasolaryngoscopy showed a growth in the left nasal fossa and biopsy revealed a poorly differentiated nasopharyngeal carcinoma that exhibited positive immunostaining for ACTH. The second patient presented with a 10-month history of bone pain over both lower limbs. She was normocalcemic but her serum alkaline phosphatase was markedly elevated. A bone biopsy showed both osteoclastic and osteoblastic activity with widespread fibrosis suggestive of Paget's disease. Three months later, she developed third cranial nerve palsy. Computed tomography investigation revealed a soft tissue mass filling the sphenoid and ethmoid sinuses. Biopsy showed a poorly differentiated nasopharyngeal carcinoma. The bone biopsy was reviewed and immunohistochemistry demonstrated the presence of cells positive for the epithelial marker AE1/3 within the fibrous stroma. Radio-labeled in situ hybridization showed that Epstein-Barr virus early RNA was present in these tumor cells and the bone lesions were in fact metastases. CONCLUSIONS: Nasopharyngeal carcinoma can present with rather atypical symptoms that may lead to a delay in diagnosis. Therefore, in high risk populations, it is important to consider nasopharyngeal carcinoma as a possible primary tumor in patients with occult carcinomas.

ACTH Syndrome, Ectopic↗
PubMed1996

Regeneration of immature mammalian spinal cord after injury.

In this review we describe the growth of regenerating fibres through lesions in immature mammalian spinal cord. In newborn opossums and foetal rats, repair occurs rapidly and reliably without antibodies, implants or bridges of undamaged spinal cord. In the neonatal opossum one can compare recovery from lesions made to the CNS at various stages of development in the animal and in culture. As the CNS matures, the capacity for regeneration ceases abruptly. In particular, the extracellular matrix and molecules associated with glia have been shown to play a role in promoting and inhibiting regeneration. Major problems concern the precision with which regenerating axons become reconnected to their targets, and the specificity needed for recovery of function.

Animals↗
PubMed1996

Spermatocytic seminoma: a clinicopathological review of ten patients.

Spermatocytic seminoma is an uncommon variety of testicular neoplasm, differing from its classical counterpart at both clinical and pathological levels and having a low propensity to metastasize. This is a retrospective review of ten patients with pathologically confirmed and reviewed disease who were seen at the Royal Marsden Hospital. All patients presented as Stage I. Five were treated with radiotherapy and five have undergone surveillance. The median age was 56.5 years. The median follow-up is 8 years and no patient has relapsed. Two have died of intercurrent disease. Our series supports others of a similar size in the literature with respect to both the rarity and the good prognosis of spermatocytic seminoma. With only one case of relapse confirmed in the literature, this is a subgroup of patients in whom radiotherapy can safely be omitted.

Combined Modality Therapy↗
PubMed1996

An analysis of surveillance for stage I combined teratoma--seminoma of the testis.

We analysed 973 patients with stage I testicular tumours presenting between 1983 and 1994. The median ages at presentation for non-seminomatous germ cell tumour (teratoma) were 27 years, seminoma 36 years and combined tumour 33 years. These differences were statistically significant (Mann-Whitney P < 0.05), suggesting that combined tumours may have a separate natural history. We, therefore, analysed all stage I patients managed with surveillance (530 in total) post orchidectomy. The actuarial 5 year relapse-free survival and anatomical patterns of relapse were identical for non-seminomatous germ cell tumour (NSGCT) and combined tumour and both were statistically distinct from seminoma (P = 0.01, log-rank test, chi-square test P = 0.001). The association of seminoma within a histologically confirmed NSGCT has no influence on the clinical outcome.

Adult↗
PubMed1996

Characterization of P1-purinoceptors on rat isolated duodenum longitudinal muscle and muscularis mucosae.

1. P1-purinoceptors mediating relaxation of the rat duodenum longitudinal muscle and contraction of the rat duodenum muscularis mucosae were characterized by the use of adenosine and its analogues, 5'-N-ethylcarboxamidoadenosine (NECA), N6-cyclopentyl-adenosine (CPA), N6-(phenylisopropyl)adenosine (R-PIA), 2-chloroadenosine (2-CADO) and 2-p-((carboxyethyl)phenethylamino)-5'-carboxamidoadenosine (CGS21680), as well as the P1-purinoceptor antagonist 8-phenyltheophylline (8-PT) and the A1-selective antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX). 2. In the rat duodenum longitudinal muscle, the order of potency of the adenosine agonists was CPA > NECA > adenosine > CGS21680. DPCPX antagonized responses to CPA and NECA at a concentration of 1 nM suggesting that they are acting at A1 receptors. A Schild plot versus CPA gave a slope near to unity (slope = 0.955) and a pA2 of 9.8 confirming that CPA was acting via A1 receptors. Schild analysis for DPCPX versus NECA, however, gave a slope of 0.674 suggesting that NECA was acting on both A1 and A2 receptors. CGS21680, a selective A2a agonist, was much less potent than adenosine suggesting that the A2 receptors are of the A2b subtype. 3. In the rat duodenum muscularis mucosae, the order of potency of the adenosine agonists was NECA > or = R-PIA = CPA > 2-CADO > adenosine, and DPCPX antagonized responses to CPA and NECA at a concentration of 1 microM. CGS21680, at a concentration of 10 microM, had no effect on this tissue. This suggests the presence of A2 receptors in this tissue and that they are of the A2b subtype. 4. These results are in agreement with previous studies in the whole duodenum showing the presence of A1 and A2b receptors causing relaxation, and this shows that the longitudinal muscle dominates the response of the whole tissue. In addition, a contractile A2b receptor has been revealed on the muscularis mucosae, the first time this subtype has been reported to elicit an excitatory response in a smooth muscle preparation.

Adenosine↗
PubMed1995

The mRNAs for the three chains of human collagen type XI are widely distributed but not necessarily co-expressed: implications for homotrimeric, heterotrimeric and heterotypic collagen molecules.

In cartilage collagen type XI exists as heterotrimeric molecules composed of alpha 1(XI), alpha 2(XI) and alpha 3(XI) subunits. Messenger RNAs for some of the alpha chains of collagen type XI have also been found in non-chondrogenic tissues but the chain composition of the molecule in these sites is not known. Some non-chondrogenic tissues also contain heterotrimers containing collagen alpha 2(V) and alpha 1(XI) chains. We have explored the possibility that collagen type XI could exist in differing trimeric forms in non-chondrogenic tissues and aimed to predict the subunit composition of this collagen in those tissues. The distribution and relative levels of expression of collagen alpha 1(XI), alpha 2(XI) and alpha 3(XI)/alpha 1(II) mRNAs in different human fetal tissues were studied. Expression of mRNAs for all three genes of collagen type XI is not restricted to cartilage but is widespread. However, in some non-chondrogenic tissues, the mRNAs for all three alpha chains of collagen type XI were not co-expressed, but collagen alpha 1(XI) and alpha 2(XI) mRNAs were found either singly or without collagen alpha 3(XI) transcripts. Collagen type XI may therefore exist as homotrimers and/or heterotrimers composed of two collagen alpha(XI) chains in some tissues. The distribution of mRNAs for collagen alpha 2(V) and alpha 1(I) were also studied. Co-expression of collagen type XI, alpha 2(V) and alpha 1(I) mRNAs was found for many tissues. These findings have implications for the possibility of additional chain associations for collagen types XI and V in cross-type heterotrimers within heterotypic fibrils.

Cartilage↗
PubMed1995

Tissue-specific and differential expression of alternatively spliced alpha 1(II) collagen mRNAs in early human embryos.

Expression of the alpha 1(II) procollagen gene is not confined to chondrogenic tissues during vertebrate development. Transcripts of the human gene (COL2A1) are alternatively spliced to give mRNAs which either exclude (type IIB mRNA) or include (type IIA mRNA) an exon encoding a cysteine-rich domain in the amino-propeptide. The distribution of COL2A1 mRNAs in 27- to 44-day human embryos and 8- to 24-week fetuses was studied by in situ hybridization and RNase protection analyses. Type IIA mRNAs were expressed in prechondrogenic cells and were also preferentially expressed in chondrogenic tissues at regions of chondrocyte commitment and cartilage growth. During maturation of chondrocytes, there is a switch to expression of type IIB mRNAs. In non-chondrogenic tissues of early embryos, type IIA mRNA expression was associated with active tissue remodeling, epithelial organization, and sites of tissue interaction. Type IIA mRNAs were also expressed in some non-chondrogenic tissues where expression had previously been undetected, such as the tooth bud, liver, adrenal cortex, apical ectodermal ridge, and indifferent gonad. In older fetuses type IIA mRNAs were the sole or major transcript in most non-chondrogenic tissues except the choroid plexus and tendon. In the meninges there was a unique switch from type IIB to type IIA expression. The expression pattern of COL2A1 transcripts suggests that, in addition to contributing to the structural integrity of the cartilage extracellular matrix, type II procollagen may serve a morphogenetic role in embryonic development. Our findings clearly show that the pattern of expression of type II procollagen mRNAs is largely conserved between man and mouse. However, some differences exist, and these should be taken into consideration when animal models are used to study human diseases associated with COL2A1.

Alternative Splicing↗
PubMed1995

High-dose carboplatin and etoposide for salvage chemotherapy of germ cell tumours.

We evaluated high-dose carboplatin and etoposide with autologous bone marrow stem cell support in the salvage treatment of patients with metastatic germ cell tumours who had failed previous chemotherapy. The treatment programme comprised initial conventional dose chemotherapy. 23 patients received a first cycle of high-dose treatment, and 12 who showed no evidence of progression had a second cycle 2-3 months later. 8 of the 23 patients treated with high-dose chemotherapy are alive in remission 4-29 months from the start of high-dose treatment. 3 of these 8 required further treatment for recurrence. In the initial part of the study, the dose of carboplatin was escalated in successive patients. Grade 3/4 treatment-related toxicity occurred in 4 of 18 patients (1 fatal) who received carboplatin doses to give a AUC (area under the serum concentration/time curve) of 30 mg.min/ml or less and 3 of 5 patients (2 fatal) who received higher doses. We, therefore, recommend 30 mg.min/ml for further evaluation in chemotherapy sensitive patients.

Adolescent↗
PubMed1995

Nine-month changes of maternal expressed emotion in conduct and emotional disorders of childhood: a follow-up study.

In this follow-up study, mothers of 28 children with conduct disorders (CD) and 29 children with emotional disorders (ED) of 6-11 years of age, were interviewed and rated for expressed emotion 9 months after their first clinical assessment. Mothers of children with CD expressed significantly less criticism and higher warmth after 9 months. Initial externalizing scores in the CD group and initial internalizing scores in the ED group at the first assessment predicted symptomatic change, in contrast with EE scales. Initial externalizing scores and low levels of maternal warmth predicted presence of conduct disorder at the last contact with the clinician. The implications of the findings on the development of treatment techniques are discussed.

Affective Symptoms↗
PubMed1995

Expression of immune regulatory molecules in Epstein-Barr virus-associated nasopharyngeal carcinomas with prominent lymphoid stroma. Evidence for a functional interaction between epithelial tumor cells and infiltrating lymphoid cells.

Undifferentiated nasopharyngeal carcinomas (UNPC) are characterized by an association with Epstein-Barr virus and an abundant lymphoid stroma. The role of this lymphoid stroma is uncertain but is mostly thought to represent an immune response against viral or tumor antigens. We have analyzed the expression of immune regulatory receptor/ligand pairs in snap-frozen biopsies of 20 UNPCs. All cases were Epstein-Barr virus positive and the virus-encoded latent membrane protein, LMP1, was expressed in 6 cases. By immunohistochemistry, we have demonstrated the expression of CD70 and CD40 in the tumor cells of 16 and 18 cases, respectively. Infiltrating lymphoid cells expressing CD27, the CD70 receptor, and the CD40 ligand were present in all cases. The Bcl-2 protein was detected in 17 cases. Unexpectedly, tumor cells of 5 cases expressed at least one member of the B7 family (CD80, CD86, and B7-3) and many lymphoid cells expressing the corresponding counter-receptor, CD28, were detected in all cases. Interestingly, 5 of 6 LMP1-positive cases also expressed B7, whereas all 14 LMP1-negative cases were also B7 negative. Our results indicate that T cells and carcinoma cells communicate in the microenvironment of UNPCs and suggest that the presence of a lymphoid stroma may be a requirement for UNPC growth at least in certain stages of tumor development.

Carcinoma↗
PubMed1994

Application of a composite faecal egg count procedure in diagnostic parasitology.

Egg counts from a simple composite faecal counting procedure using equal amounts of sample from ten sheep were compared statistically against the arithmetic means of the same ten samples prepared by a conventional egg counting method. Forty separate data sets were analysed in an untransformed bivariate plot and after natural logarithmic transformation. A sign test analysis indicated a high degree of similarity between the two data sets. A confidence interval for the composite count (n = 10) was calculated to give a result between five eggs more and 15 eggs less than the arithmetic mean count of the ten samples. When multiple faecal samples are to be examined, the composite method has significant advantages in time saving and increased throughput whilst still providing an accurate result. This technique has been used to monitor gastrointestinal helminthosis and for faecal egg count reduction testing to assess anthelmintic efficacy.

Animals↗