A phase II trial of 9-aminocaptothecin (9-AC) as a 120-h infusion in patients with non-small cell lung cancer

In a previous phase II trial of the synthetic topoisomerase I inhibitor, 9-aminocamptothecin (9-AC), given as a 72-h infusion, we identified modest single agent activity of 9% in patients with previously untreated advanced non-small cell lung cancer (NSCLC). Preclinical studies suggested that a more prolonged continuous infusion of the drug might lead to greater antitumor activity. A phase I study recommended a phase II dose of 25 microg/m2/hr for 120 h (3000 microg/m2 over 5 days), administered for 2 consecutive weeks of a 3-week cycle. We utilized this schedule and enrolled 13 chemotherapy-naïve patients with Stage IIIB and IV NSCLC in this trial: median age 67 (range 57-74); 46% male; 92% stage IV; and median performance status 1. Twelve patients are available for response and toxicity evaluation after 2 cycles of therapy. One patient achieved a partial response. Four patients had stable disease while seven patients had progressive disease. Patients with stable or progressive disease after two cycles received no additional 9-AC, and were offered conventional chemotherapy. The median survival time was 10.2 months and the one-year survival rate 28% (95% confidence interval, 5-58%). Significant toxicities included myelosuppression, fatigue, and anorexia. One patient had grade 4 neutropenia following the first week of cycle 2, and did not receive additional therapy. There were no neutropenia-related infections. These data suggest that this prolonged schedule is unlikely to increase 9-AC's very modest activity in NSCLC above that seen with the simpler 72-h administration schedule. Further evaluation of 9-AC in NSCLC is not recommended.

Frequency downconversion and phase noise in MIT

High-frequency (3-30 MHz) operation of MIT systems offers advantages in terms of the larger induced signal amplitudes compared to systems operating in the low- or medium-frequency ranges. Signal distribution at HF, however, presents difficulties, in particular with isolation and phase stability. It is therefore valuable to translate received signals to a lower frequency range through heterodyne downconversion, a process in which relative signal amplitude and phase information is in theory retained. Measurement of signal amplitude and phase is also simplified at lower frequencies. The paper presents details of measurements on a direct phase measurement system utilizing heterodyne downconversion and compares the relative performance of three circuit configurations. The 100-sample average precision of a circuit suitable for use as a receiver within an MIT system was 0.008 degrees for input amplitude -21 dBV. As the input amplitude was reduced from -21 to -72 dBV variation in the measured phase offset was observed, with the offset varying by 1.8 degrees. The precision of the circuit deteriorated with decreasing input amplitude, but was found to provide a 100-sample average precision of <0.022 degrees down to an input amplitude of -60 dBV. The characteristics of phase noise within the system are discussed.

Multifocal chorioretinal atrophy associated with herpes zoster ophthalmicus

A 73-year-old woman developed multiple depigmented lesions in the fundus 4-6 months after an episode of acute Herpes zoster ophthalmicus. Post-mortem examination of the globe 15 years after this acute episode confirmed multiple old chorioretinal scars probably due to vasculitis of the short posterior ciliary arteries and branches. Patchy old infarcts were also noted in the iris.

Frontline talk: teachers' linguistic resources when talking about mental health and illness

Talk about mental health and mental illness was examined using Potter and Wetherell's system of discourse analysis. Participants were 8 health coordinators (teachers) from a range of New Zealand secondary schools. They were interviewed on the topics of mental health and mental illness. Verbatim transcripts from the interviews were analyzed, and three mental health and illness linguistic resources were identified: a mental health as illness resource, a mental well-being resource, and a mental illness resource. Each resource was examined, and the practical consequences of this language use was discussed in relation to the role of teachers as frontline mental health professionals.

Bipolar disorders: new approaches to therapy

This article reviews the evidence supporting different somatic treatment strategies in the acute and maintenance treatment phases of bipolar disorder. Bipolar affective disorder is a chronic disorder with a life time incidence of 0.3 - 1.5/100 [1]. Severe affective disorder is associated with a risk of completed suicide of 6 - 15% [2,3]. Traditionally, bipolar disorder has been considered as an episodic disorder with good inter-episode recovery [4]. This is being increasingly challenged with patients demonstrating social, marital, occupational and cognitive dysfunction, even when euthymic [5]. The management of bipolar disorder should be considered in the context of; the type of episode, this may be manic, depressed or mixed; the degree and rate of recovery; the cycling frequency and precipitant, if any, for recurrence and the onset and evolution of the underlying illness. On average, four episodes occur every 10 years. However 13 - 24% of patients develop rapid cycling disorder, in which four or more episodes occur within a year. Patients with bipolar disorder often have co-morbid anxiety and substance abuse. Moreover, axis I co-morbidity may be associated with an earlier age at onset and worsening course of bipolar illness. [6]. Axis II co-morbidity is also common, this was highlighted in a study by Kay and colleagues who, after excluding patients with a history of alcohol misuse, demonstrated axis II co-morbidity in almost a quarter of euthymic bipolar patients [7]. Good practice relies on an overall management plan that incorporates somatic, psychological and social approaches. This paper will focus on one element of such a plan, the currently available somatic management strategies for bipolar disorder.

DNA contamination of mortuary instruments and work surfaces: a significant problem in forensic practice?

A study of 20 mortuaries was undertaken to assess whether contamination of instruments, tables and cutting areas due to residual material containing human DNA after routine cleaning is an actual or only a theoretical problem. Of the 20 mortuaries studied, 50% were found to have material containing quantifiable human DNA on the instruments and surfaces sampled. This DNA was amplified and found, in some cases, to have been derived from at least three people. Of those that did not yield measurable amounts of DNA, a number of samples were selected at random, amplified and were found to produce partial profiles indicating the presence of low levels of human DNA. The possible sources of human DNA from mortuaries are discussed as well as means to reduce or irradicate the problem of instrument contamination. Finally the implications of these findings for forensic investigations are discussed.

The pathophysiology of different types of leg ulcers

Leg ulcers are wounds on the leg of 6 weeks or more duration, and may range in size from very small to very large. They are caused primarily by deterioration in the peripheral circulation of the affected individual, although this may arise from a number of conditions. This article discusses the major conditions leading to the formation of a leg ulcer, in order to improve understanding of the rationale for leg ulcer management techniques.

Sequenced allelic ladders and population genetics of a new STR multiplex system

The advent of PCR technology and use of short tandem repeat (STR) loci improves throughput and reduces costs whilst a high level of discrimination can be achieved. A new system, comprising seven STRs, was developed to compliment the existing systems. This paper describes the preparation of allelic ladders of the most commonly observed alleles of a new STR multiplex system (third generation; TGM multiplex); all alleles have been sequenced. Meioses studies estimated a mutation rate of 0-0.4% across loci. Statistical independence was investigated by employing exact tests; chi(2)-tests and excess homozygosity tests. The results demonstrated that the allele proportions do not differ from those expected and that there was no consequential dependence between loci. The discriminating power of the system was examined using 295 Caucasian, 140 Afro-Caribbean and 212 Asian unrelated samples, and was found to be approximately 1 in 50 million, 1 in 85 million and 1 in 20 million for each of these groups, respectively.

The support that mentors receive in the clinical setting

This paper looks at the support systems that mentors in a trust both need and have. It was a study to examine the causes of stress within mentoring with a view to exploring this aspect of the role and to examine the clinical learning environment. The English National Board (ENB) has stated that mentoring is a requirement for all nurse training. The literature speaks of the importance of the role of the mentor to the student. There has also been research showing that this role is stressful and needs support if it is to be fully effective. However, there is little research into the nature and quality of the support received or required by mentors. This study addresses issues that had not been previously addressed in that it looks at the nature of the support required by the mentors to enable them to perform their duties both to the student and to the patients in their care. The study is largely ethnographic in nature. It consists of a short series of unstructured interviews of selected experienced mentors as a means of collecting data to enable the construction of a questionnaire that was submitted to all mentors within the trust. This is to allow the trust and educational institution to work on developing newer and better support systems both for the present placement and also for future placements.

Incidence of incomplete excision in surgically treated basal cell carcinoma: a retrospective clinical audit

All the patients who had excision of basal cell carcinoma at the regional plastic surgery unit at Manchester over a period of 2 years from January 1995 to December 1996 were included in a retrospective audit. A total of 879 lesions were excised in 754 patients. In 41 lesions (4.7%) the tumour was incompletely excised, 16 of these lesions were further excised; the rest were managed by regular follow-up. The mean age of the incomplete excision group was slightly higher. The site where the incomplete excision rate was highest was the scalps followed by the ear, canthi,eyebrows and nose. There was a higher incidence of squamous differentiation and presence of foci of squamous cell carcinoma in the lesions excised incompletely. There was no statistically significant difference among the different groups of surgeons but in individual grades the rate was lower where more wounds were repaired by direct closure. The concept of a complexity ratio (number of wounds repaired by other methods/number of wounds repaired by direct closure) can be helpful in comparing the incomplete excision rates of different grades of surgeons or departments. The excision of basal cell carcinoma is one of the commonest procedures performed by all grades of surgeons in a plastic surgery department. Incomplete excision leads to further surgery or prolonged follow-up, thus significantly affecting the outcome. As the incidence of incomplete excision can be precisely monitored, it may be a useful tool for clinical governance.

Effect of hydrocortisone on the pituitary response to growth hormone releasing hormone

RATIONALE

In depression, the growth hormone (GH) response to clonidine and L-tryptophan (L-TRP) is reduced, suggesting reduced alpha2-adrenergic and serotonin (5-HT)1A receptor function. Pretreatment with hydrocortisone (100 mg, orally 11 h before) also blunts the GH response to L-TRP. This effect may be mediated at the hypothalamic level via reduced 5-HT1A receptor function or at the pituitary level, either by a direct effect on somatotrope cells or via enhanced insulin-like growth factor-1 (IGF-1) or somatostatin (SS) release.

OBJECTIVES

To examine the effects of acute and chronic exposure to hydrocortisone on baseline and stimulated GH release from the pituitary.

METHODS

Twelve healthy male volunteers received pretreatment with acute hydrocortisone (100 mg, 11 h before), chronic hydrocortisone (20 mg twice a day for 1 week) and placebo in a double blind, balanced order, crossover design. Serial measurements of plasma GH, IGF-1 and thyroid stimulating hormone (TSH) levels were made at baseline and following intravenous administration of 1 mcg/kg GHRH.

RESULTS

The GH response to growth hormone releasing hormone (GHRH) was significantly blunted by pretreatment with both acute and chronic hydrocortisone. Baseline IGF-1 levels were significantly lower at baseline after chronic hydrocortisone compared with placebo. Baseline TSH levels were significantly lower after acute hydrocortisone compared with placebo, suggesting an increase in somatostatin levels.

CONCLUSIONS

These data suggest that hydrocortisone acts at the pituitary level to reduce GH release. The TSH and IGF-1 data support the hypothesis that hydrocortisone reduces GH release by enhancing somatostatin and IGF-1 release.

Antitumor imidazolyl disulfide IV-2 causes irreversible G(2)/M cell cycle arrest without hyperphosphorylation of cyclin-dependent kinase Cdk1

Aberrant function of redox-regulated proteins is a possible cause for cellular transformation and loss of cell cycle control. The small protein thioredoxin has oncogenic properties and controls cell cycle movement through G(1), S, and G(2)/M phases. The redox-active, asymmetrical 1-methylpropyl-2-imidazolyl disulfide (IV-2) has previously been shown to react with and inhibit thioredoxin activity in vitro, the proliferation of human tumor cells in culture, and the growth of tumors in mice. We now examined the effects of IV-2 on cell cycle progression. In synchronized tsFT210 mouse mammary carcinoma cells, IV-2 halted cells in mitosis. In asynchronously growing MCF-7 human breast cancer cells, IV-2 exclusively and irreversibly blocked cells in G(2)/M at concentrations that correlated with its growth inhibitory activity. Neither the closely related, less redox active 2-hydroxy-1-methylpropyl-2-imidazolyl disulfide (AIV-2), which differs from IV-2 only by an additional hydroxyl group, nor the symmetrical diallyl disulfide caused a G(2)/M arrest under these conditions. Furthermore, MCF-7 cells treated with IV-2 showed increased Cdk1 kinase activity and a decrease in Cdk1 tyrosine phosphorylation, indicating that IV-2 did not directly inhibit Cdk1 or Cdc25 activities. IV-2 did, however, increase Bcl-2 phosphorylation. These data suggest that the thioredoxin inhibitor IV-2, despite its simple structure, is able to target redox-sensitive processes that are critical for cell cycle progression through mitosis. The results are also consistent with a role of thioredoxin regulating cell cycle progression through G(2)/M.

Update on collagen receptor interactions in platelets: is the two-state model still valid?

This review summarises some of the key developments that have taken place in our understanding of platelet-collagen interactions within the last 18 months. Within this time, the major activatory collagen receptor glycoprotein VI (GPVI) has been sequenced and shown to reconstitute collagen responses in a megakaryocytic cell line. It is a member of the Ig superfamily of proteins, with two extracellular Ig domains, and is constitutively associated with the Fc receptor gamma-chain (FcR gamma-chain). GPVI signals through a pathway that shares many features with those of immune receptors, with critical roles for Syk and the adapters LAT and SLP-76 in the activation of PLCgamma2. Significant developments have also taken place in regard to the role of the major adhesion receptor for collagen, the integrin alpha2beta1 (also known as GPIa-IIa). An alpha2beta1-selective collagen-based peptide has been developed and co-crystallised with the I-domain of the alpha2 subunit. Polymorphisms in alpha2 have been shown to cause wide variation in expression of alpha2beta1, with the alpha2 allele T807/A873 leading to a high level of the integrin and increased risk of stroke in young people. Activation of platelets by a wide range of agonists has been shown to increase the affinity of alpha2beta1 to intermediate or high affinity states. This has important implications for the two-site, two-state model of collagen-platelet interactions. A new model is proposed in which collagen binds initially to either alpha2beta1 or GPVI, leading to subsequent binding to the other receptor and conversion of the integrin to a high affinity state. In this model, both receptors generate intracellular signals which support platelet activation.

Dopamine D1 and adenosine A1 receptors form functionally interacting heteromeric complexes

The possible molecular basis for the previously described antagonistic interactions between adenosine A(1) receptors (A(1)R) and dopamine D(1) receptors (D(1)R) in the brain have been studied in mouse fibroblast Ltk(-) cells cotransfected with human A(1)R and D(1)R cDNAs or with human A(1)R and dopamine D(2) receptor (long-form) (D(2)R) cDNAs and in cortical neurons in culture. A(1)R and D(1)R, but not A(1)R and D(2)R, were found to coimmunoprecipitate in cotransfected fibroblasts. This selective A(1)R/D(1)R heteromerization disappeared after pretreatment with the D(1)R agonist, but not after combined pretreatment with D(1)R and A(1)R agonists. A high degree of A(1)R and D(1)R colocalization, demonstrated in double immunofluorescence experiments with confocal laser microscopy, was found in both cotransfected fibroblast cells and cortical neurons in culture. On the other hand, a low degree of A(1)R and D(2)R colocalization was observed in cotransfected fibroblasts. Pretreatment with the A(1)R agonist caused coclustering (coaggregation) of A(1)R and D(1)R, which was blocked by combined pretreatment with the D(1)R and A(1)R agonists in both fibroblast cells and in cortical neurons in culture. Combined pretreatment with D(1)R and A(1)R agonists, but not with either one alone, substantially reduced the D(1)R agonist-induced accumulation of cAMP. The A(1)R/D(1)R heteromerization may be one molecular basis for the demonstrated antagonistic modulation of A(1)R of D(1)R receptor signaling in the brain. The persistence of A(1)R/D(1)R heteromerization seems to be essential for the blockade of A(1)R agonist-induced A(1)R/D(1)R coclustering and for the desensitization of the D(1)R agonist-induced cAMP accumulation seen on combined pretreatment with D(1)R and A(1)R agonists, which indicates a potential role of A(1)R/D(1)R heteromers also in desensitization mechanisms and receptor trafficking.