Transition in endocrinology: predictors of drop-out of a heterogeneous population on a long-term follow-up

PURPOSE

To evaluate: (1) clinical and epidemiological characteristics of outpatients transitioned from Pediatrics Endocrine (PED) to Adult Endocrine Department (AED) in a tertiary center; (2) transition process features, and predictors of drop-out.

METHODS

Demographic, clinical, and transition features of 170 consecutive patients with pediatric onset of chronic endocrine or metabolic disease (excluded type 1 diabetes) who transitioned from PED to AED (2007-2020) were retrospective evaluated.

RESULTS

The age at transition was 18.4 ± 4 years (F:M = 1.2: 1), and mean follow-up 2.8 years. The population was heterogeneous; the most (69.4%) was affected by one, 24.1% by two or more endocrine diseases, 6.5% were followed as part of a cancer survivor's surveillance protocol. The comorbidity burden was high (37, 20.6, and 11.2% of patients had 2, 3, 4, or more diseases). The number of visits was associated with the number of endocrine diseases and the type of them. Adherent subjects had a higher number of comorbidities. Thyroid disorders and more than one comorbidity predicted the adherence to follow-up. Having performed one visit only was predictive of drop-out, regardless of the pathology at diagnosis.

CONCLUSION

This is the first study that analyzed a specific transition plan for chronic endocrine diseases on long-term follow-up. The proposed "one-size-fits-all model" is inadequate in responding to the needs of patients. A structured transition plan is an emerging cornerstone.

Respiratory and muscular response to acute non-metabolic fatigue during ramp incremental cycling

We tested the hypothesis that acute, non-metabolic fatigue, by reducing maximal power output and possibly increasing muscle recruitment at a given exercise intensity, will reduce indexes of exercise tolerance during incremental cycling. Ten subjects performed three ramp incremental tests respectively after static stretching (STRC), dropjumps (DJ) or control (CTRL). Fatigue was assessed as reduction in maximal power output (_sprintPO) during isokinetic sprints. During the ramps we measured: oxygen consumption (VO₂), power output (PO), and surface electromyography. _sprintPO was reduced after STRC and DJ (p = 0.007) yet not after CTRL. During the ramps, the interventions augmented muscle excitation vs CTRL (p ≤ 0.001). Peak PO and VO₂ were reduced after STRC (302 ± 39W p = 0.033, 3365 ± 465 ml/min p = 0.015) and DJ (300 ± 37W p = 0.023, 3413 ± 476 ml/min p = 0.094) vs CTRL (314 ± 41W, 3505 ± 486 ml/min). Interventions were associated with early occurrence of the ventilatory thresholds and increased VO₂ vs CTRL (p = 0.029). The physiological response after acute non-metabolic fatigue suggests a link between exercise intolerance and the decreased ability to produce force.

A newly identified mutation in the complement factor I gene not associated with early post-transplant recurrence of atypical hemolytic-uremic syndrome: a case report

Atypical hemolytic uremic syndrome (aHUS), which can recur after renal transplantation, is associated with poor graft outcomes. The underlying genetic defect, namely, mutations in genes coding for the complement factor H, I (CFI), or membrane cofactor protein, greatly impacts the risk of aHUS recurrence. We report here the case of a patient with chronic renal failure due to aHUS in which screening for complement mutations, performed before wait-listing for kidney transplantation, showed a never described previously heterozygous mutation in the exon II of the CFI gene. Specifically, this mutation leads to a substitution of cytosine for guanosine at nucleotide 148, resulting in the change at amino acid 50 from arginine to proline. Subsequently, he received a renal allograft from deceased donor. Good graft function was established immediately, without clinical features of aHUS. Due to a lack of data on this mutation, we avoided prophylactic treatment for aHUS but closely monitored biochemical markers of aHUS to treat a possible recurrence. Immunosuppressive treatment was based on basiliximab, tacrolimus, steroids, and mycophenolic acid. At the time of discharge the serum creatinine was 1.4 mg/dL. Ten months after transplantation the patient is doing well without evidence of aHUS. Our case suggested that a heterozygous mutation in exon II of the CFI gene was not associated with a risk of early post-transplant aHUs recurrence adding new knowledge on complement mutations implicated in aHUS post-transplant recurrences.

Focus on genetic and epigenetic events of colorectal cancer pathogenesis: implications for molecular diagnosis

Originally, colorectal cancer (CRC) tumorigenesis was understood as a multistep process that involved accumulation of tumor suppressor genes and oncogenes mutations, such as APC, TP53 and KRAS. However, this assumption proposed a relatively limited repertoire of genetic alterations. In the last decade, there have been major advances in knowledge of multiple molecular pathways involved in CRC pathogenesis, particularly regarding cytogenetic and epigenetic events. Microsatellite instability, chromosomal instability and CpG island methylator phenotype are the most analyzed cytogenetic changes, while DNA methylation, modifications in histone proteins and microRNAs (miRNAs) were analyzed in the field of epigenetic alterations. Therefore, CRC development results from interactions at many levels between genetic and epigenetic amendments. Furthermore, hereditary cancer syndrome and individual or environmental risk factors should not be ignored. The difficulties in this setting are addressed to understand the molecular basis of individual susceptibility to CRC and to determine the roles of genetic and epigenetic alterations, in order to yield more effective prevention strategies in CRC patients and directing their treatment. This review summarizes the most investigated biomolecular pathways involved in CRC pathogenesis, their role as biomarkers for early CRC diagnosis and their possible use to stratify susceptible patients into appropriate screening or surveillance programs.

The medial cord to musculocutaneous (MCMc) nerve transfer: a new method to reanimate elbow flexion after C5-C6-C7-(C8) avulsive injuries of the brachial plexus--technique and results

The aim of this paper is to report on our ample experience with the medial cord to musculocutaneous (MCMc) nerve transfer. The MCMc technique is a new type of neurotization which is able to reanimate the elbow flexion in multilevel avulsive injuries of the brachial plexus provided that at least the T1 root is intact. A series of 180 consecutive patients, divided into four classes according to the quality of hand function, is available for a long-term follow-up after brachial plexus surgery. The patients enrolled for the study have in common a brachial plexus palsy showing multiple cervical root avulsive injuries at two (C5-C6), three (C5-C6-C7) and four (C5-C6-C7-C8) levels. The reinnervation of the musculocutaneous nerve is obtained via an end-to-end transfer from two donor fascicles located in the medial cord. The selected fascicles are those directed principally to the flexor carpi radialis, ulnaris and, to a lesser degree, the flexor digitorum profundus. Under normal anatomic conditions, they are located in the medial cord, and their site corresponds to the inverted V-shaped bifurcation between the internal contribution of the median nerve and the ulnar nerve. The technique has no failure and no complications when the hand shows a normal wrist and finger flexion and a normal intrinsic function. In case of suboptimal conditions of the hand, the technique has proved technically more challenging, but still with 67% satisfactory results. In the four-root avulsive injuries, however, this method shows its limitations and an alternative strategy should be preferred when possible. EMG analysis shows a reinnervation in both the biceps and the brachialis muscles, explaining the high quality of the observed results. Moreover, this technique theoretically offers the possibility of a "second attempt" at a more distal level in case of failure of the first surgery. This procedure is quick, safe, extremely effective and easily feasible by an experienced plexus surgeon. The ideal candidate is a patient harbouring a C5-C6 avulsive injury of the upper brachial plexus with a normally functioning hand.

Factors influencing choice of chemotherapy in metastatic colorectal cancer (mCRC)

Management of metastatic colorectal cancer requires a multimodal approach and must be performed by an experienced, multidisciplinary expert team. The optimal choice of the individual treatment modality, according to disease localization and extent, tumor biology, and patient clinical characteristics, will be one that can maintain quality of life and long-term survival, and even cure selected patients. This review is an overview of the different therapeutic approaches available in metastatic colorectal cancer, for the purpose of defining personalized therapeutic algorithms according to tumor biology and patient clinical features.

Efficacy and safety analysis of once per cycle pegfilgrastim and daily lenograstim in patients with breast cancer receiving adjuvant myelosuppressive chemotherapy FEC 100: a pilot study

Background

Neutropenia is a common toxicity in patients receiving myelosuppressive chemotherapy. In this prospective pilot study, we compared the efficacy and safety profiles of pegfilgrastim administered subcutaneously once per cycle and lenograstim administered subcutaneously daily six times per cycle, for primary neutropenia prophylaxis in women with breast cancer receiving adjuvant anthracycline-based chemotherapy.

Materials and methods

Twenty women were enrolled. All patients received epirubicin 100 mg/m² with 5-fluorouracil 500 mg/m² and cyclophosphamide 500 mg/m² on day 1 and every 21 days thereafter, according to the FEC 100 chemotherapy regimen. Eight patients received a single dose of pegfilgrastim on day 2, while 12 patients were treated with daily administration of lenograstim from days five to ten. Absolute neutrophil count and duration of grade 3–4 neutropenia were monitored using seriated blood samples. The incidence of bone pain was evaluated using the visual analog scale (VAS).

Results

The incidence of grade 3–4 neutropenia was 75% in patients who received pegfilgrastim, and 25% in patients who received lenograstim. One case of febrile neutropenia was shown in pegfilgrastim patients. The mean duration of grade 3–4 neutropenia was 2 days in pegfilgrastim group versus 1.4 days in the lenograstim group. Bone pain was present in 37.5% of pegfilgrastim patients versus 58.3% of lenograstim patients. The mean duration of bone pain in the pegfilgrastim group was 4 days versus 6 days in the lenograstim group.

Conclusion

In our experience, a single injection of pegfilgrastim was less effective for controlling neutropenia than six daily injections of lenograstim. The safety profiles of pegfilgrastim and lenograstim were similar with a lower incidence of bone pain in patients treated with pegfilgrastim.

A 68-year-old Caucasian man presenting with urinary bladder lymphoepithelioma: a case report

Introduction

Lymphoepithelioma is a very rare form of malignant tumor originating from epithelial line cells. Its occurrence has potential clinical, therapeutic and prognostic implications. In the present report we describe an unusual case of bladder cancer with two different histological varieties: transition cell carcinoma and lymphoepithelioma-like carcinoma. Lymphoepithelioma-like carcinoma of the bladder has only been rarely reported in the literature to date.

Case presentation

We present the case of a 68-year-old Caucasian man who, after occurrence of hematuria, underwent transurethral resection of a bladder tumor. The results of a histological examination confirmed a high-grade non-muscle-invasive pT1 lymphoepithelioma-like carcinoma of the urinary bladder, associated with a concurrent high-grade transition cell carcinoma. After analyzing the histological features, our patient was subjected to treatment with intra-vesical instillations of bacillus Calmette-Guérin. Our work stresses that diagnosis and therapeutic approaches can be difficult and controversial, especially in the early stages of this rare carcinoma.

Conclusions

This report emphasizes the importance of extending our knowledge and experiences regarding this uncommon carcinoma. Further studies are needed to better understand this rare disease and define more accurate diagnostic and therapeutic strategies.

Efficacy, safety, and cost-effectiveness (CE) analysis of pegfilgrastim (P) and lenograstim (L) in patients (pts) with nonmetastatic breast cancer (nmBC) receiving myelosuppressive chemotherapy (mCT)

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Background: Neutropenia (N) is common in pts who receive mCT. This retrospective study was conducted to determine efficacy, safety and cost of single injection of P (6 mg) compared with daily L (263 μg), in primary prophilaxis of N in pts affected by nmBC, who received mCT. Methods: 50 women (median age 54 years) underwent to median 6 (range 4–8) CT doses with antracyclines +/- taxanes. At every cycle, 28 pts received daily L (median 5 injections from day 5 to 9), while 22 pts received one dose of P on day 2. Absolute neutrophil count, incidence of G3/G4-N, bone pain (BP: Numerical Rate Scale >7) and CE analysis were evaluated. Results: In overall population (OP) incidence of G3-N and G4-N was 25% and 68%, respectively in L vs 22.7% and 41%, respectively in P; two cases (7%) of febrile N (FN) occurred in pts treated with L and three cases (13.6%) of FN in P. In 19 pts treated with FEC100 (10 pts L vs 9 pts P) we observed 0% of G3-N and 30% of G4-N in L while 33% of G3-N and 44% of G4-N in P. 31 pts received TAC/AC+T (18 pts L vs 13 pts P) with G3-N and G4-N 38.8% and 66.6%, respectively in L vs 15.3% and 30.7%, respectively in P. 18.2% of pts, who received P, had BP vs 35.7% in L. Reduction of CT doses was observed in 35.7% in L vs 41% in P. In Italy the cost of 1 injection of P was about 1489,00 euro compared with about 655,00 euro for 5 injections of L. Conclusions: In our experience, 1 injection of P was more effective and expensive than 5 daily administration of L to control N in OP and in particular in TAC/AC+T, while in FEC100, L was satisfactory with good CE profile. No difference about incidence of NF. Safety of P and L were similar with a lower incidence of BP in P.

Nonpegylated liposomal doxorubicin (nPLD) in neoadjuvant treatment of local advanced breast cancer (LABC) patients (pts)

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Background: Anthracycline is very effective in treatment of breast cancer, however it can cause cardiac toxicity events. nPLD has greater safety profile and comparable efficacy than conventional anthracyclines. We evaluated safety and efficacy, in neoadjuvant setting, of nPLD in pts with LABC. Methods: 11 pts (median age 57 years). Their clinical stage was: stages IIA and IIB 1 pt respectively, IIIB 7 pts, IIIC 2 pts. 8 pts presented at diagnosis with cT4 disease. All pts were treated with nPLD (50 mg/mq, d1q21) plus Docetaxel (75 mg/mq, d1q21) and Cyclophosphamide (500 mg/mq, d1q21); only 1 pt received Cyclophosphamide, nPLD and Trastuzumab. At beginning of therapy, overall population had left ventricular ejection fraction (LVEF) ≥55%. Results: After a median of 4 chemotherapy cycles, we observed following clinical response: stable disease 2 pts (18%); partial response 7 pts (64%); complete response 2 pts (18%). 9 pts were evaluable for radiological response: objective response rate and clinical benefit were 78 % and 100% respectively. 8 pts underwent surgery, in 3 pts was performed breast-conserving surgery. At the definitive histological examination pathologic stage was: IA 4 pts (50%), IIIA 1 pts (12,5%), IIIB 2 pts (25%) and IIIC 1 pts (12,5%). 2 pts experienced cardiac toxicity: 1 pt had an atrial fibrillation G2 while 1 pt had an symptomatic decline of LVEF G3 after first cycle, causing interruption of treatment. Other pts not showed clinically significant reduction of LVEF (>5%). Conclusions: Despite small number of pts, our experience suggests a safety profile and efficacy of nPLD in neoadjuvant settings for LABC; breast conservation was possible in 3 pts, in other pts (73%) this was not possible mainly for the advanced stage (T4).

“Long extended” temozolomide in a selected population with not radically resected high-grade gliomas

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Background: Despite the important progress in the treatment of solid tumors, high grade gliomas (HGGs) remain neoplasm with poor prognosis, especially when are not radically resected. Here we report the results of a selected population treated with standard schedule of Radiotherapy (RT) + Temozolomide (TMZ) followed by TMZ until progression. Methods: From January 2008 to January 2010, 14 newly diagnosed HGG patients, with median age of 50.6 years (range 27-75 yrs), were enrolled at Oncology Unit of S. Maria Goretti Hospital in Latina (University of Rome “Sapienza”). All patients were not radically resected and with ECOG PS=O. Furthermore patients were selected according to O6 Methyl-Guanine-DNA-Methyl Transferase (MGMT) promoter methylation status. Only methylated patients were included in our study. After surgery, patients received standard treatment with TMZ (75 mg/m2) concomitant with RT (60 Gy total dose). After a break of six weeks, Magnetic Resonance Imaging (MRI) was performed and all patients with stable or responsive disease received TMZ (150mg/200mg/m2/d x 5dq 28d) until progression. The response to treatment was evaluated according to RANO criteria Results: In our study the results showed one year overall survival (OS) and progression free survival (PFS) rates of 85,7% and 71,4% respectively. Moreover we observed two years OS rate of 70% and two years PFS rate of 10%. A total of 108 cycles of adjuvant TMZ were administered with average number of 9 per patient (range 1-16). The most frequent side effects observed were haematological toxicity and fatigue. Thrombocytopenia (G2-G3) was observed in 42% of patients, neutropenia (G2-G3), fatigue (G2-G3) and nausea (G2-G3) in 30%, 32% and 25% of patients respectively. Conclusions: Despite the small number of patients, our experience suggests a manageable safety profile and a good efficacy of TMZ until progression in a selected population of patients (HGGs not radically resected, with a good ECOG PS). These data also confirms the literature knowledge, underlining the prognostic positive impact of MGMT promoter methylation in patients with HGG.

Incidence of chemotherapy (CT)-induced amenorrhea in premenopausal patients (pts) with breast cancer (BC) following adjuvant anthracycline (A), cyclophosphamide (C), and taxane (T)

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Background: CT may induce amenorrhea or menopause to a variable extent. These side-effects may impair or impede fertility, cause sexual dysfunction, bone loss and menopausal symptoms in many women. We analyzed incidence of amenorrhea in premenopausal pts affected by BC treated with CT. Methods: In this retrospective study we evaluated the incidence of amenorrhea in 24 premenopausal BC pts (43 median age years) treated with adjuvant A + C +/- T based CT. Overall population (OP) had regular menstrual cycle and no pts began hormone therapy, at the same time. Results: 10 pts (42%) received only A + C, 6 pts (25%) received A + C + T, 8 pts (33%) received A + C and after T. In 22 pts (92%) amenorrhea appeared during CT; in particular, 9/10 pts (90%) treated with A + C , 5/6 pts (83%) with A + C + T and 8/8 pts (100%) with A + C and after T. In OP amenorrhea appeared during first three cycles of CT in 18 pts (82%) and particularly 7 pts (32%) after 1 cycle, 7 pts (32%) after 2 cycles, 4 pts (18%) after 3 cycles and 4 pts (18%) in subsequent doses. Amenorrhea occurred within the first two doses of treatment in 14/22 pts (64%); in 6/9 pts (66.7%) treated with A + C, in 4/5 pts (80%) with A + C + T and in 4/8 (50%) with A + C and after T. In 7 pts (32%), median age 40 years, at the end of CT reappeared menstrual cycle. Conclusions: In our small experience the incidence of amenorrhea during CT was extremely high and there are no differences between subgroups undergoing to CT with A + C alone or combined with T. In the group of pts in which T were given concomitant with A and C, amenorrhea occurred earlier than the other two groups. Menstrual cycle reappeared at the end of CT in younger pts.

[Kidney retransplantation: indications and limits]

Whether or not to consider a uremic patient for retransplantation remains a matter of debate. Donor shortage and putative poor outcomes are the main cons, improved results in the last decade and a better survival (HR 0.50) with retransplantation than dialysis stand as pros. The percentage of patients waitlisted for retransplantation or already having been retransplanted is increasing (up to 20-30%) and the absolute contraindications are limited to rare conditions (loss of previous transplant due to anti-glomerular basement antibodies in Alport's syndrome, early recurrence of GNF or hemolytic uremic syndrome). When retransplantation is considered, however, careful screening for risk factors is mandatory, whether they are related to the previous graft or to the recipient's clinical features or the donor's demographics and immunological status. In the last decade the clinical outcomes of retransplantation have significantly improved. No difference in patient survival at the fifth year has been reported between first, second and third grafts. The kidney survival at the same interval is above 70% for the second graft and 65% for the third graft. Nephrectomy of a previous graft is not necessary if not for clinical reasons. As far as the maximum number of retransplants is concerned, most transplant centers (69%) set no clear-cut limit. In conclusion, also taking into account that many patients after graft failure ask for readmission to the waiting list (75% in our experience), we think the retransplantation option should always be evaluated.

Enhancement of anxiety, facilitation of avoidance behavior, and occurrence of adult-onset obesity in mice lacking mitochondrial cyclophilin D

In this report, we have assessed the behavioral responses of mice missing the Ppif gene (CyPD-KO), encoding mitochondrial cyclophilin D (CyPD). Mitochondrial CyPD is a key modulator of the mitochondrial permeability transition which is involved in the regulation of calcium- and oxidative damage-induced cell death. Behavioral screening of CyPD-KO mice (ranging between 4 and 15 months of age) was accomplished using a battery of behavioral paradigms which included testing of motor functions, exploratory activity, and anxiety/emotionality, as well as learning and memory skills. We found that, compared with wild-type mice, CyPD-KO mice were (i) more anxious and less explorative in open field and elevated plus maze and (ii) performed better in learning and memory of avoidance tasks, such as active and passive avoidance. However, the absence of CyPD did not alter the nociceptive threshold for thermal stimuli. Finally, deletion of CyPD caused also an abnormal accumulation of white adipose tissue resulting in adult-onset obesity, which was not dependent on increased food and/or water intake. Taken together, our results suggest a new fundamental role of mitochondrial CyPD in basal brain functions and body weight homeostasis.

Surfactant self-assembling in gas phase: electrospray ionization- and matrix-assisted laser desorption/ionization-mass spectrometry of singly charged AOT clusters

The self-assembling of sodium bis (2-ethylhexyl) sulfosuccinate (AOT) in gas phase has been investigated by electrospray ionization- and matrix-assisted laser desorption/ionization mass spectrometry. Large surfactant clusters with an aggregation number close to that found in apolar media have been observed either as positive or negative ions. Moreover, the marked predominance of singly charged species as well as preliminary theoretical calculations strongly suggest an aggregate structure characterized by an internal hydrophilic core hosting the extra charge surrounded by an apolar shell constituted by the surfactant alkyl chains. This structure is similar to that of the more familiar reversed micelles formed when an appropriate surfactant is solubilized in apolar solvents. Finally, similar trends are observed independently either on the ionization technique or the polarity of the solvent used. This, together with the large dependence of the aggregation number on the flow rates, strongly indicates that self-assembling of the surfactant molecules occurs during the evaporation step.

Alveolar soft part sarcoma in children and adolescents: A report from the Soft-Tissue Sarcoma Italian Cooperative Group

BACKGROUND

Alveolar soft part sarcoma (ASPS) is a rare malignant tumor and little is known about its clinical features and management. We report on a series of 19 pediatric patients managed over 20 years.

PATIENTS AND METHODS

Primary conservative surgery was performed in all patients and was radical in nine, non-radical in three; seven patients underwent biopsy alone (3 unresectable tumors, 4 metastatic disease). In two cases radical surgery was performed after primary chemotherapy. Radiotherapy was delivered to 8 patients, chemotherapy to 15.

RESULTS

After a median follow-up of 74 months, the five-year survival was 80% for the whole series, 91% for patients with localized disease, 100% for patients with tumor < or = 5 cm, and 31% for those > 5 cm; 16 of 19 patients were alive (12 of 12 with grossly-resected tumor in first continuous remission). Chemotherapy achieved two partial remission among seven evaluable patients.

CONCLUSIONS

Pediatric ASPS has a more favorable prognosis than its adult counterpart. In this series, tumor size correlates with metastatic disease at onset and is the major factor influencing survival. Surgery is the mainstay of therapy. The effectiveness of adjuvant therapy remains to be established, though radiotherapy may be advisable in cases of inadequate surgery.

Biochemical and genetic analysis of the mitochondrial response of yeast to BAX and BCL-X(L)

The BCL-2 family includes both proapoptotic (e.g., BAX and BAK) and antiapoptotic (e.g., BCL-2 and BCL-X(L)) molecules. The cell death-regulating activity of BCL-2 members appears to depend on their ability to modulate mitochondrial function, which may include regulation of the mitochondrial permeability transition pore (PTP). We examined the function of BAX and BCL-X(L) using genetic and biochemical approaches in budding yeast because studies with yeast suggest that BCL-2 family members act upon highly conserved mitochondrial components. In this study we found that in wild-type yeast, BAX induced hyperpolarization of mitochondria, production of reactive oxygen species, growth arrest, and cell death; however, cytochrome c was not released detectably despite the induction of mitochondrial dysfunction. Coexpression of BCL-X(L) prevented all BAX-mediated responses. We also assessed the function of BCL-X(L) and BAX in the same strain of Saccharomyces cerevisiae with deletions of selected mitochondrial proteins that have been implicated in the function of BCL-2 family members. BAX-induced growth arrest was independent of the tested mitochondrial components, including voltage-dependent anion channel (VDAC), the catalytic beta subunit or the delta subunit of the F(0)F(1)-ATP synthase, mitochondrial cyclophilin, cytochrome c, and proteins encoded by the mitochondrial genome as revealed by [rho(0)] cells. In contrast, actual cell killing was dependent upon select mitochondrial components including the beta subunit of ATP synthase and mitochondrial genome-encoded proteins but not VDAC. The BCL-X(L) protection from either BAX-induced growth arrest or cell killing proved to be independent of mitochondrial components. Thus, BAX induces two cellular processes in yeast which can each be abrogated by BCL-X(L): cell arrest, which does not require aspects of mitochondrial biochemistry, and cell killing, which does.

Men and women holding hands: whose hand is uppermost?

This study explored the issue of whether status and power differences are expressed in the way men and women hold hands. It was hypothesized that men's hands would be upper in heterosexual handholding couples significantly more often than women's. Also, to explore the possibility that height differences of handholding partners might affect handholding position, all handholding couples observed in this study were classified as couples with men and women of equal height or couples where either the men or women were taller. A total of 1,006 handholing couples were observed, and men's hands were significantly more likely to be the upper one in couples when men were taller than women and in couples where men and women were of equal height, suggesting that, while height does matter, it is less important for this handholding pattern than sex differences.

Two modes of activation of the permeability transition pore: the role of mitochondrial cyclophilin

Mitochondria possess an inner membrane channel, the permeability transition pore, which is inhibited by cyclosporin A (CsA) and by matrix protons. As suggested recently by our laboratory, pore closure by these inhibitors may be due to dissociation of mitochondrial cyclophilin (CyP-M), a matrix peptidyl-prolyl-cis-trans isomerase, from its putative binding site on the pore. Unbinding of CyP-M would follow a CsA-dependent or proton-dependent change in conformation of the CyP-M molecule. It is interesting that upon binding of CsA the enzymatic activity of CyP-M is inhibited, but it is not clear whether this event plays a role in pore inhibition. Here we report experiments designed to further test the role of CyP-M in pore function. Our results indicate that CyP-M-dependent and independent mechanisms of pore activation may exist, and that the peptidylprolyl-cis-trans-isomerase activity of CyP-M is not necessarily involved in pore modulation by CyP-M.

Interactions of cyclophilin with the mitochondrial inner membrane and regulation of the permeability transition pore, and cyclosporin A-sensitive channel

Mammalian mitochondria possess an inner membrane channel, the permeability transition pore (MTP), which can be inhibited by nanomolar concentrations of cyclosporin (CS) A. The molecular basis for MTP inhibition by CSA remains unclear. Mitochondria also possess a matrix cyclophilin (CyP) with a unique N-terminal sequence (CyP-M). To test the hypothesis that it interacts with the MTP, we have studied the interactions of CyP-M with rat liver mitochondria by Western blotting with a specific antibody against its unique N terminus. Although sonication in isotonic sucrose at pH 7.4 refraction sediments with submitochondrial particles at 150,000 x g. We show that the interactions of this CyP-M pool with submitochondrial particles are disrupted (i) by the addition of CSA, which inhibits the pore, but not of CSH, which does not, and (ii) by acidic pH condition, which also leads to selective inhibition of the MTP; furthermore, we show that the effect of acidic pH on CyP-M fully prevents the inhibitory effect of H+ on the MTP (Nicolli, A., Petronilli, V., and Bernardi, P. (1993) Biochemistry 32, 4461-4465). These data suggest that CyP-M inhibition by CSA and protons may be due to unbinding of CyP-M from its putative binding site on the MTP. A role for CyP-M in MTP regulation is also supported by a study with a series of CSA derivatives with graded affinity for CyP. We show that with each derivative the isomerase activity of CyP-M purified to homogeneity is similar to that displayed at inhibition of MTP opening, CyP-M (but not CyP-A) and decreased efficiency at MTP inhibition is obtained by substitution in position 8 while a 4-substituted, nonimmunosuppressive derivative is a as effective as the native CSA molecule, indicating that calcineurin is not involved in MTP inhibition by CSA.